Cell membranes are relatively simple structures yet are critical to the function of cells.
They are a perfect example of how the evolving model of cell membranes changed over
the years with the development of new technologies available to cell and molecular
biologists.
a. What were Langmuir’s and Gorter and Grendel’s contributions to our cell membrane
model?
b. What was the major contribution of freeze fracture to our current model of the cell
membrane?
c. What was the major contribution of the cell fusion and "capping/patching"
experiments described in class to our current model of the cell membrane?
d. List two virtues of red blood cells that are not shared with other cell types which
made them critical to the history of the evolution of our cell membrane model

Polyunsaturated fats, such as omega-3 and omega-6 fatty acids, are more susceptible to rancidity than saturated and monounsaturated fats.

This is because they have more double bonds in their structure, which are susceptible to oxidation by free radicals, heat, and light. The oxidation process can cause the fats to become rancid, producing off-flavors and odors, and reducing their nutritional value.

Rancid fats are also potentially harmful to health as they can produce harmful compounds that may contribute to inflammation and chronic diseases. Therefore, it is important to store and handle polyunsaturated fats carefully to prevent rancidity.

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The genetic drift effect that would limit natural selection is the Founder effect.

Genetic drift is the random fluctuation of allele frequencies, especially in small populations. Genetic drift happens due to the probability of inheritance, which causes some alleles to become more or less common than they would be if the alleles were transmitted only by chance.

Genetic drift is a phenomenon that occurs in all populations, although its effects are more significant in small populations.

The founder effect is a type of genetic drift that occurs when a new population is established from a small group of individuals who are genetically isolated from the larger population.

However, the founder effect can limit the gene pool's diversity, making it difficult for natural selection to operate effectively. As a result, the founder effect can limit natural selection's ability to shape the genetic composition of populations.

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If a plant population grows larger than the carrying capacity of its ecosystem, there will be a shortage of resources like water, nutrients, and space that are necessary for survival and reproduction.

This will lead to increased competition among individuals for these limited resources, which will result in a decrease in the overall health and vitality of the population. The plants may also become more susceptible to disease and predation, and their growth and reproduction rates may decline.

Over time, the population may experience a decline in numbers as individuals die off or fail to reproduce successfully, until it reaches a size that is sustainable by the available resources in the ecosystem.

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The major function of calcium is homeostatic balance. Calcium is an essential mineral for maintaining homeostasis in the body.

Homeostasis is the body's ability to maintain a stable internal environment even when there are external changes. The regulation of calcium levels in the body is a vital function of homeostasis.

Calcium ions play an essential role in muscle contractions, nerve function, blood clotting, and bone and teeth development.

Calcium's functions in the human body include:

Assists in the formation and growth of teeth and bones.

Helps with blood clotting.

Maintains proper nerve function.

Helps muscles contract and relax.

Assists in maintaining healthy blood pressure levels.

Calcium is a mineral that our bodies need to function correctly. Calcium is not made by the body, so we must acquire it from our diet.

Dairy products, leafy green vegetables, and other calcium-fortified products are excellent sources of calcium.

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The total number of ATPs generated from 7 acetyl-CoA molecules is 131.5 ATPs.

The breakdown of one acetyl-CoA molecule in the citric acid cycle generates 3 NADH molecules and 1 FADH2 molecule, which can be used to produce ATP through oxidative phosphorylation. Based on the given information, 2.5 ATPs are generated per NADH and 1.5 ATPs are generated per FADH2.

Therefore, the total ATPs generated from 7 acetyl-CoA molecules can be calculated as follows:

Total ATPs generated from 7 acetyl-CoA molecules = ATPs generated from NADH + ATPs generated from FADH2 + ATPs generated from substrate-level phosphorylation (7 x 10 ATPs) = 52.5 + 10.5 + 70 = 131.5 ATPs.

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Explanation: Each newly formed DNA strand joins with an original DNA strand to form a new double helix. DNA is a large polymer molecule made up of repeating nucleotides.

Answer: Biotic components are the living things that have a direct or indirect influence on other organisms in an environment

Explanation:

brainliest?

Messenger RNA (mRNA) is a cellular component that transports instructions from the nucleus's DNA to the cytoplasmic locations where proteins are synthesized (the ribosomes)

What purposes does cytoplasm serve?

The ability of cells to keep their turgidity, which allows the them to maintain their shape, is one of the cytoplasm's primary tasks. Here are some of the cytoplasm's additional functions: All of the components of the organism's cells and organelles are embedded in the jelly-like cytoplasm, which is inside of the cell membrane and is made up of salt and water.

Why does the cytoplasm of prokaryotic cells exist?

The basic genetic material of prokaryotic cells is also found in the cytoplasm since these cells lack a distinct nuclear membrane. In contrast to eukaryotes, these cells are typically smaller and have a basic internal cytoplasm architecture. The cytoplasm stands out from other fluids because it is unique to the physical universe.

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After ovulation, high levels of progesterone inhibit the secretion of B. FSH and LH.

The process of ovulation is complex and tightly controlled by various hormones. The endocrine system is responsible for the production and release of hormones. Hormones regulate various physiological processes and play a vital role in the functioning of the body. The follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are two essential hormones that play a significant role in the process of ovulation. The FSH and LH hormones are secreted by the anterior pituitary gland, and they are essential for regulating the menstrual cycle.


During the menstrual cycle, the levels of FSH and LH hormones increase, causing the development of follicles in the ovary. The follicles are responsible for producing estrogen, which is essential for the development of the endometrial lining of the uterus. Once ovulation occurs, the follicle that contains the egg is transformed into a corpus luteum. The corpus luteum is responsible for producing progesterone, which is essential for the maintenance of the endometrial lining of the uterus. High levels of progesterone inhibit the secretion of FSH and LH hormones. The inhibition of FSH and LH hormones results in the prevention of further follicle development and ovulation. The corpus luteum will continue to produce progesterone until the levels of progesterone drop.

If pregnancy occurs, the developing embryo will secrete  the human chorionic gonadotropin (HCG) hormone. The HCG hormone will stimulate the corpus luteum to continue producing progesterone to support the pregnancy. If pregnancy does not occur, the corpus luteum will degenerate, causing the levels of progesterone to drop, leading to menstruation
Therefore, high levels of progesterone inhibit the secretion of FSH and LH hormones after ovulation, resulting in the prevention of further follicle development and ovulation. Therefore the correct option is B

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The following which are the type of the mRNA processing are 5' G Cap, 3' Poly A tail and Removal of introns option A, C and F.

Messenger RNA (mRNA) is a cellular molecule that transports codes from DNA in the nucleus to the cytoplasmic locations where proteins are synthesised (the ribosomes). Scientists Elliot Volkin and Lazarus Astrachan initially characterised the molecule that would later be known as mRNA in 1956. Ribosomal RNA (rRNA) and transfer RNA are the other two main forms of RNA in addition to mRNA (tRNA).

Post-transcriptional modifications are the processes by which pre-mRNA undergoes some chemical modifications to produce a mature and functional mRNA that can synthesize protein.

Three major modifications are:

RNA splicing - Non-coding introns are removed, only the expressed exons are joined together to form functional mRNA.

Poly 'A' tailing - Multiple adenosine monophosphates are added to the 3' end of mRNA.

5' Capping - Addition of methylated Guanine nucleotides to the 5' end of mRNA.

Both Poly A tailing and 5' capping,

Protects from enzymatic digestion of nucleases

Helps in exporting mRNA from nucleus to cytoplasm

Helps in translation process.

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The option that correctly identifies how prokaryote phylogenies differ from mammal phylogenies is: There is a high degree of lateral gene transfer in prokaryotes, but not in mammals.

Phylogeny refers to the evolutionary history of an organism or group of organisms. Phylogenies indicate the connections between distinct organisms or groups of organisms. It describes a cluster of organisms linked by a single ancestor from the past.A prokaryote phylogeny, on the other hand, differs significantly from mammal phylogenies. In a mammalian phylogeny, there is a low degree of lateral gene transfer. Lateral gene transfer is defined as the movement of genetic material between two unicellular organisms that aren't direct descendants.

As a result, when constructing a mammalian phylogeny, one can rely solely on the organisms' genomic DNA sequence as evidence.However, in a prokaryote phylogeny, there is a high degree of lateral gene transfer. In this case, constructing phylogenies using DNA sequences can be challenging because some genes may come from other bacterial cells. Instead of DNA, RNA sequences are used to create prokaryote phylogenies. Thus, the correct option is: There is a high degree of lateral gene transfer in prokaryotes, but not in mammals.

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'Organisms prokaryotes are single-celled organisms that only have circular DNA, while eukaryotes have linear DNA and can be unicellular or multicellular.

The difference between eucaryotes and prokaryotes in terms of chromosomes is based on the fact that eukaryotes are more complex and therefore they have more genetic material that may be divided into one or more linear chromosomes.

Therefore, with this data, we can see that differences in eukaryotes and prokaryotes in terms of chromosomes depend on the shape and number of pdf chromosomes.

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Greenhouse gases are gases in the Earth's atmosphere that trap heat and contribute to the greenhouse effect, which is the process by which the Earth's atmosphere keeps the planet's temperature within a certain range that is habitable for life. The most common greenhouse gases are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and fluorinated gases.

Several ways to reduce greenhouse gas emissions are as follows:

Reducing fossil fuel usage: One of the most important ways to reduce greenhouse gas emissions is by reducing the usage of fossil fuels. This includes decreasing the consumption of petroleum, natural gas, and coal.

Renewable Energy: Another way to reduce greenhouse gas emissions is by using renewable energy such as solar, wind, hydroelectric, and geothermal energy sources. The energy generated from these sources is clean and does not emit greenhouse gases.

Reducing deforestation: Forests play a significant role in reducing the amount of carbon dioxide in the atmosphere. However, due to deforestation, carbon dioxide is released into the atmosphere. Therefore, reducing deforestation is crucial in reducing greenhouse gas emissions.

Reducing waste: The management of waste is also crucial in reducing greenhouse gas emissions. Waste produces methane which is a potent greenhouse gas. Therefore, reducing waste through recycling, composting, and other methods will help reduce greenhouse gas emissions.

Reducing water usage: Reducing water usage is also important in reducing greenhouse gas emissions. The energy used to pump, treat, and heat water results in the emission of greenhouse gases. Therefore, reducing water usage can reduce greenhouse gas emissions.

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Defining the following terms ligament, tendon, cartilage, ossification, fracture, and dislocation as follows:

Ligament: A ligament is a fibrous connective tissue that connects bones and often acts to stabilise and hold tissues together.

Tendon: Muscles and bones are connected by fibrous connective tissue called tendons. Tendons can join muscles to objects like the eyeball. A tendon helps a bone or other structure move.

Cartilage: Your joints and bones are protected by cartilage, a sturdy, flexible connective tissue. It serves as your body's overall shock absorber.

Ossification: The process of forming bones is called osteogenesis or bone ossification. Between the sixth and seventh weeks of embryonic development, this process starts, and it lasts until roughly age 25.

Fracture: A fracture is a break in the bone. An open or complicated fracture occurs when a shattered bone punctures the skin. Fractures are usually caused by vehicle accidents, falls, or sports injuries.

Dislocation: A dislocation occurs when two bones separate where they meet at a joint. This type of damage can be excruciatingly painful and temporarily distort and immobilise the joint. Dislocations are most commonly found in the shoulders and fingers, although they can also occur in the elbows, knees, and hips.

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Answer: C

Explanation: Echoes are produced when a sound wave is reflected back on hitting an obstacle in its path. The reflected sound wave will then travel back to the source. This depicts the process involved in the working of the SONAR.

Answer:

the answer to "sonar works by" is:

C. measuring the reflection rate of sound waves off objects

Explanation:

An acoustic transducer is used in modern active sonar systems to create a sound wave that is reflected off target objects.

The respiratory system plays an important role in maintaining the acid-base balance/buffer of blood by regulating the levels of carbon dioxide (CO2) and bicarbonate (HCO3-) ions in the body.

When carbon dioxide is absorbed into the bloodstream, it combines with water to generate carbonic acid (H2CO3), which then breaks down into hydrogen ions (H+) and bicarbonate ions. (HCO3-). Because this reaction is reversible, it can change based on the body's concentrations of carbon dioxide and bicarbonate ions. The respiratory system assists in controlling the quantities of carbonic acid and bicarbonate ions in the body, which in turn aids in maintaining the pH of the blood within a specific range.

By absorbing or releasing hydrogen ions (H+) in reaction to variations in acidity, a buffer is a material that helps a solution resist pH changes.

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In an area of the body where blood was relatively acidic (low ph), you can predict that the enzymes will be affected or deactivated because of the change in the pH value.

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The apicomplexans are parasitic and infect with special cells called sporozoites. Apicomplexans, a phylum of parasitic unicellular organisms, includes several of the most important protozoan parasites of humans and other animals.

Here, correct option is C.

Many different kinds of hosts are infected by these protozoans, which are ubiquitous and have a significant influence on global human and animal health. Plasmodium (the cause of malaria), Toxoplasma, and Cryptosporidium are some of the most well-known genera. A sporozoite is an infectious stage in the life cycle of some parasitic protozoans.

Sporozoites are usually the form of the pathogen that is transmitted to the definitive host by an intermediate host. Sporozoites, like other protozoan life-cycle stages, are unicellular and lack many of the features found in cells of multicellular organisms, but they are capable of infecting a wide range of hosts because they have evolved to be adapted to a particular host or group of hosts in many cases.

Therefore, correct option is C. apicomplexans.

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The type of bone that is arranged in concentric layers is called compact bone or cortical bone. Compact bone is denser than spongy bone, making it stronger and more resistant to bending or fracturing.

The concentric layers, also called lamellae, are made up of collagen fibers and mineral deposits that provide structural support to the bone.

Red marrow is found inside the spongy bone, specifically in the cavities of long bones such as the femur and the humerus, as well as in the flat bones of the skull, pelvis, and ribs. Red marrow is responsible for producing red blood cells, white blood cells, and platelets, which are necessary for oxygen transport, immune function, and blood clotting. In contrast, yellow marrow is found in the central cavity of long bones and is primarily composed of adipose tissue (fat).

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In fruit flies, the long wing allele is dominant over the vestigial wing allele. Of them, 128 had long wings and 128 had vestigial wings, with long wings making up 101 of the total. Option 2 is Correct.

Long wings result from the dominant V allele, whereas vestigial wings result from the recessive V allele. We refer to a trait's inheritance pattern as recessive when it requires two copies of the same allele to display a certain phenotype. For instance, the vestigial phenotype is transmitted via recessive genes. A vestigial fly must have the genotype vg/vg.

In this 192 progeny were created when heterozygous long winged flies and vestigial winged flies were bred. Due to a deficiency in their "vestigial gene," located on the second chromosome, flies with vestigial wings are unable to fly. Option 2 is Correct.

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Correct Question:

In fruit flies, allele for long wing is dominant to the allele for vestigial wing. When heterozygous long winged flies were crossed with vestigial winged flies, 192 offsprings were produced. Of these 101 had long wing & 91 had vestigial wings.

1. If an exact Mendelian ratio had been obtained, then the number of each phenotype would have been Long winger - 64Vestigial winged - 128 with Long winger - 96

2. Vestigial winged - 96 and Long winger - 128

3. Vestigial winged - 64 and Long winger - 192

4. Vestigial winged.

In a Central Texas grassland, the producers incorporate 12,000 kJ of energy from the sun into their tissues. B. 1,200 kJ energy would be incorporated into the tissues of herbivores.

The 10% rule of energy transfer in a food chain is a general guideline that describes the amount of energy that is transferred between trophic levels in an ecosystem. It states that only about 10% of the energy available in one trophic level is transferred to the next trophic level.

In the case of the Central Texas grassland, the producers are the first trophic level, which converts about 12,000 kJ of solar energy into organic matter through photosynthesis. When herbivores consume these producers, they only assimilate about 10% of that energy into their tissues, while the remaining 90% is lost as heat or used for metabolic processes such as respiration.

This means that the amount of energy that is available to the herbivores from the producers is only about 10% of 12,000 kJ, or 1,200 kJ. Therefore, herbivores in the Central Texas grassland would incorporate approximately 1,200 kJ of energy into their tissues.

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The molecular mass of the haploid human genome is:1.99 x 10¹² g, the weight of 1 copy of the human haploid genome is, 1.99 x 10¹² g, the number of copies of the VNTR, D1S80 added to the PCR is 1.29 x 10¹¹ copies, and Both strands of the D1S80 allele can be amplified during PCR. Because the PCR process involves the use of two primers.

Step 1: Molecular mass of haploid human genome

The haploid human genome contains 3.2 x 10⁹ base pairs

The average molecular mass of a base pair is 660 g/mol

Avogadro's number is 6.02 x 10²³

Therefore, the molecular mass of the haploid human genome is:

3.2 x 10⁹ base pairs × 660 g/mol × 6.02 x 10²³ = 1.99 x 10¹² g

Step 2: Weight of 1 copy of the human haploid genome

The weight of one copy of the haploid human genome is equal to the weight of the entire haploid genome divided by the number of copies (which is 1)

Therefore, the weight of 1 copy of the human haploid genome is:

1.99 x 10¹² g / 1 = 1.99 x 10¹² g

Step 3: Number of copies of the VNTR, D1S80 added to PCR

The isolated DNA solution has a concentration of 90 ng/µL

When 5 µL of the isolated DNA is added to the PCR, the amount of DNA added is:

90 ng/µL x 5 µL = 450 ng

We know that 1 copy of the haploid human genome weighs 3.5 x 10⁻¹² g, so we can calculate the number of copies of the VNTR, D1S80 added to the PCR:

450 ng / (3.5 x 10⁻¹² g/copy) = 1.29 x 10¹¹ copies

Both strands of the D1S80 allele can be amplified during PCR. This is because the PCR process involves the use of two primers, one for the forward strand and one for the reverse strand. The primers are designed to bind specifically to the ends of the target DNA region, and both strands will be replicated during the amplification process. Therefore, both strands of the D1S80 allele will be amplified.

The number of copies of the primers added to the PCR depends on the amount of primer solution added. If 3 µL of a 5 µM primer solution is added to the PCR, the number of copies of the primers added is:

3 µL x 5 µM x 6.02 x 10²³ molecules/mol x 660 g/mol / 3.5 x 10⁻¹² g = 2.83 x 10⁹ copies of each primer

If you had 100 copies of the template DNA, there would be enough primers to support 30 cycles of PCR. In theory, the amount of template DNA doubles with each cycle of PCR. After 30 cycles, the amount of DNA would have doubled 30 times, which is 2³⁰ times the starting amount. This is approximately 10⁹ times the starting amount, which is more than enough to support PCR amplification.

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The characteristics of a squid that make it an animal include movement and sensory organs, and these characteristics and adaptations demonstrate that the squid is an animal that is highly adapted to survive in its aquatic environment.

There are several ways to identify a squid as an animal. Here are some details about its functions and adaptations that help it survive:

Movement: Squids are highly mobile and are able to move through the water quickly and efficiently. They have a streamlined body shape and fins that allow them to swim with ease.

Sensory organs: Squids have a complex nervous system with large, highly developed eyes that allow them to detect and respond to changes in their environment. They also have sensitive tentacles that can detect touch and taste.

Feeding: Squids are carnivorous and use their tentacles to catch prey. They have a sharp beak that they use to break apart their food, and a radula (a tongue-like organ covered in tiny teeth) that helps them scrape food from surfaces.

Reproduction: Squids have a complex reproductive system and are capable of producing large numbers of offspring. They have a special mating ritual that involves the male transferring sperm packets to the female, who stores them until she is ready to lay eggs.

Adaptations: Squids have several adaptations that help them survive in their environment. For example, they have an ink sac that they can use to confuse predators and make a quick escape. They also have the ability to change the color and texture of their skin to blend in with their surroundings and avoid detection.

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The equation that best represents the overall equation for photosynthesis is: 6 CO2 + 6 H2O + Light energy → C6H12O6 + 6 O2

Photosynthesis is the process in which green plants, algae, and cyanobacteria convert light energy into chemical energy, which is stored in the form of glucose or sugar, which is utilized for nourishment or energy at a later time. The process of photosynthesis occurs in the chloroplasts of the plant cell, which contains chlorophyll pigment that traps light energy and converts it into chemical energy, which is then utilized for various metabolic activities.

The process of photosynthesis involves two types of reactions: light-dependent reactions and light-independent reactions. In the light-dependent reactions, the chlorophyll pigment traps the light energy and converts it into chemical energy, which is utilized for various metabolic activities such as ATP production and NADPH formation.In the light-independent reactions or Calvin cycle, the carbon dioxide and water molecules are utilized to form glucose or sugar, which is the end product of photosynthesis.

The overall equation for photosynthesis is as follows: 6 CO2 + 6 H2O + Light energy → C6H12O6 + 6 O2. The reactants of photosynthesis are carbon dioxide, water, and light energy, while the products are glucose or sugar and oxygen.

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This statement is not accurate. An immunoglobulin molecule is not typically referred to as a monomer. A monomer is a single unit of a molecule, whereas an immunoglobulin molecule is made up of four polypeptide chains.

Immunoglobulins, also known as antibodies, are proteins produced by the immune system in response to the presence of foreign substances called antigens.  

A Y-shaped immunoglobulin molecule, also known as an antibody, is made up of four polypeptide chains, two heavy chains, and two light chains, which are held together by disulfide bonds. These chains form a monomer unit that contains two identical antigen-binding sites.

Immunoglobulins play a critical role in the immune system's ability to recognize and eliminate pathogens such as viruses, bacteria, and parasites, as well as foreign substances like toxins. They also play a role in preventing infections and in protecting against future infections by providing immunity.

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Answer:

The skin

Explanation:

Answer:

the skin

Explanation:

Skin is the largest external organ, which is similar to the cell membrane......

The other person is still correct tho :)

The plant group that is characterized by the innovation of pollen and allowed them to colonize low-water environments is called the gymnosperms.

Gymnosperms are a group of plants that includes conifers, cycads, Ginkgo, and gnetophytes. They are called gymnosperms because they do not have enclosed seeds like angiosperms, instead, their seeds are exposed on the surface of cones or other structures.

The innovation of pollen eliminated the need for water to transport sperm to the egg, making it possible for these plants to colonize drier environments. This adaptation was critical in the evolution and diversification of gymnosperms, making them one of the most successful and widespread plant groups on Earth.

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All four organisms belong to phylum Chordata, animalia kingdom.

The taxonomic group of creatures known as the Phylum Chordata is distinguished by the development of pharyngeal gill slits, a dorsal nerve cord, and a notochord. Animals classified as chordates differ widely in kind, from fish and amphibians to birds and mammals like humans.

A flexible structure resembling a rod that runs the length of the body, the notochord offers support and facilitates mobility. The animal's back is covered in a ribbon of nerves called the dorsal nerve cord, which carries messages from the brain to the rest of the body.

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