ati teas 7 science

Correct Answer: B

Rationale: The correct answer is B: Cerebrospinal fluid. This is the protective fluid that surrounds the brain and spinal cord. It acts as a cushion, providing mechanical protection, and helps to maintain a stable environment for the central nervous system. Blood (A) does not directly surround the brain and spinal cord. Myelin sheath (C) is a protective covering of nerve fibers, not the fluid surrounding the brain and spinal cord. Insulin (D) is a hormone involved in regulating blood sugar levels and is not the fluid that protects the brain and spinal cord.

Correct Answer: D

Rationale: The correct answer is D because water's unique polarity allows it to dissolve a wide range of substances. Water's polar covalent bonds enable it to form hydrogen bonds with other molecules, facilitating dissolution. Water's ability to dissolve various substances is crucial for biological processes such as nutrient absorption and waste removal. Choice A is incorrect because water is neutral in terms of its pH, not inherently having a neutral pH. Choice B is incorrect because water actually has a high specific heat capacity, which is why it can absorb and release large amounts of heat without significant temperature changes. Choice C is incorrect because while water does have polar covalent bonds, this property alone does not fully characterize water as much as its dissolving capabilities do.

Correct Answer: D

Rationale: The correct answer is D: Aorta. The aorta is responsible for pumping oxygenated blood to the body. This happens after the oxygenated blood leaves the left ventricle of the heart through the aortic valve. The aorta is the largest artery in the body and carries blood to all parts of the body, supplying oxygen and nutrients. The other choices are incorrect because: A: Right ventricle pumps deoxygenated blood to the lungs. B: Left ventricle pumps oxygenated blood to the body. C: Pulmonary artery carries deoxygenated blood from the heart to the lungs for oxygenation.

Correct Answer: C

Rationale: The correct answer is C: Polypeptide. Translation is the process in which mRNA is decoded by ribosomes to synthesize a specific polypeptide. During translation, transfer RNA (tRNA) molecules bring specific amino acids to the ribosome based on the mRNA codons, and these amino acids are joined together to form a polypeptide chain. The other choices are incorrect because translation does not result in the production of DNA (A), lipids (B), or carbohydrates (D). Translation specifically involves the synthesis of polypeptides, making choice C the correct answer.

Correct Answer: B

Rationale: The correct answer is B: Synapse. The synapse is the point of contact between a motor neuron and a muscle fiber where communication occurs via neurotransmitters like acetylcholine to initiate muscle contraction. A: Sarcomere is a structural unit of a muscle fiber, not the point of contact for communication. C: Tendon is a fibrous connective tissue that attaches muscle to bone, not involved in neuron-muscle communication. D: Myofibril is a cylindrical organelle within muscle fibers where muscle contractions occur, but it is not the specific point of contact for neuron communication.