Science TEAS Practice Test

Correct Answer: D

Rationale: The correct answer is D: Homeostasis. The endocrine system is responsible for regulating various physiological processes to maintain internal balance, or homeostasis, within the body. Hormones released by endocrine glands help control metabolism, growth, reproduction, and other functions. Choice A (Heartbeat) is controlled by the cardiovascular system, not the endocrine system. Choice B (Respiration) is controlled by the respiratory system. Choice C (Electrolyte and water balance) is regulated by the kidneys and not directly by the endocrine system. Thus, the primary function of the endocrine system is to maintain homeostasis through hormone regulation.

Correct Answer: A

Rationale: Step-by-step rationale for answer A: 1. Oxygenated blood from the lungs enters the left atrium. 2. It then passes through the mitral valve into the left ventricle. 3. Upon contraction, it is pumped into the aorta. 4. The oxygenated blood is then dispersed to tissues through a network of arteries and capillaries. Summary of why other choices are incorrect: B: Incorrect because oxygenated blood does not go to the right side of the heart. C: Incorrect because there is no direct connection between the left atrium and the right aorta. D: Incorrect because there is no septal valve and oxygenated blood is not stored in the left ventricle.

Correct Answer: A

Rationale: Failed to generate a rationale after 5 retries.

Correct Answer: C

Rationale: The correct answer is C: Epidermis. The epidermis is the outermost layer of the skin and is avascular, meaning it does not contain blood vessels. This is important for maintaining its protective function and preventing blood loss in case of injury. The hypodermis (A) contains blood vessels that supply the skin with nutrients and regulate temperature. The dermis (B) is rich in blood vessels, providing nourishment to the skin and regulating temperature. Option D (Hyperdermis) is not a recognized layer of the skin, making it an incorrect choice.

Correct Answer: C

Rationale: The correct answer is C: Covalent. In DNA, sugar and phosphate molecules are joined together by covalent bonds. Covalent bonds involve sharing of electrons between atoms, providing a strong and stable connection. This type of bond is essential for the structural integrity of the DNA molecule. A: Hydrogen bonds are important in DNA structure, but they connect the nitrogenous bases, not sugar and phosphate. B: Ionic bonds involve the transfer of electrons between atoms, not sharing, and are not typically involved in connecting sugar and phosphate in DNA. D: "Overt" is not a recognized type of chemical bond; it is an incorrect distractor.