During embryonic development, which of the following germ layers forms the nervous system?
A. Ectoderm
B. Endoderm
C. Mesoderm
D. Exoderm
The three germ layers that form during embryonic development are the ectoderm, mesoderm, and endoderm. The ectoderm is the outermost layer, and it gives rise to the skin, hair, nails, and nervous system. The nervous system develops from a specialized region of the ectoderm called the neural plate, which invaginates to form the neural tube. The neural tube ultimately gives rise to the brain and spinal cord, which make up the central nervous system, as well as the peripheral nervous system. The endoderm gives rise to the lining of the digestive and respiratory tracts, while the mesoderm gives rise to the musculoskeletal system, circulatory system, and several other organs. The exoderm is not a germ layer and does not exist during embryonic development.
Therefore, the Correct Answer is A.
More Questions on TEAS 7 Science
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Q #1: What is the role of the epididymis in sperm maturation?
A. The epididymis produces sperm cells.
B. The epididymis stores and protects sperm cells until ejaculation.
C. The epididymis is responsible for the transport of sperm cells from the testes to the urethra.
D. The epididymis provides nourishment to sperm cells.
Answer Explanation
The epididymis is a coiled tube located at the back of each testicle where the sperm mature and are stored until ejaculation. Sperm are produced in the testes and then transported to the epididymis where they undergo maturation and become motile. The epididymis provides a protective environment for the sperm, allowing them to mature and become more resilient to external stressors. During ejaculation, the sperm are transported from the epididymis to the vas deferens and then to the urethra for ejaculation.
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Q #2: What are the three types of salivary glands and where are they located in the mouth?
A. Parotid, sublingual, and submandibular glands located in the cheeks, tongue, and roof of the mouth, respectively.
B. Sublingual, submandibular, and buccal glands located in the tongue, cheeks, and lips, respectively.
C. Parotid, sublingual, and submandibular glands located in the roof of the mouth, cheeks, and under the jawbone, respectively.
D. Sublingual, parotid, and buccal glands located in the tongue, cheeks, and lips, respectively.
Answer Explanation
The three major pairs of salivary glands are the parotid glands, sublingual glands, and submandibular glands.
- Parotid glands are located just in front of your ears.
- Sublingual glands are located below either side of your tongue, under the floor of your mouth.
- Submandibular glands are located below your jaw.
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Q #3: Which of the following is an example of an exothermic reaction?
A. Melting ice
B. Burning wood
C. Cooking an egg
D. Dissolving sugar in water
Answer Explanation
Exothermic reactions are reactions that release energy in the form of heat, light, or sound. Burning wood is an example of an exothermic reaction because it releases heat and light. As the wood reacts with oxygen in the air, it undergoes a combustion reaction that releases energy in the form of heat and light. Melting ice is an endothermic reaction because it requires energy input to melt the solid ice into liquid water. Cooking an egg is a chemical reaction that involves denaturing the proteins in the egg, but it is not necessarily exothermic or endothermic. Dissolving sugar in water is also not an example of an exothermic reaction because it does not release energy in the form of heat, light, or sound.
