Practice TEAS Science Test

Correct Answer: A

Rationale: The correct answer is A: Skin. An organ is a group of tissues that work together to perform specific functions in the body. Skin is the body's largest organ, made up of different layers that serve various functions like protection, sensation, and regulation of body temperature. Neuron (B) is a cell type, brainstem (C) is a part of the brain, and DNA (D) is a molecule, not an organ. Skin best fits the definition of an organ, making it the correct choice.

Correct Answer: B

Rationale: The correct answer is B: Hypothalamus. The hypothalamus is responsible for maintaining homeostasis in the body by regulating various bodily functions such as body temperature, thirst, hunger, sleep, and hormonal balance. It receives input from different parts of the body and initiates responses to maintain internal stability. The brainstem (A) is involved in basic life functions like breathing and heart rate but does not play a direct role in homeostasis. The medulla oblongata (C) controls involuntary functions like breathing and swallowing. The cerebrum (D) is responsible for higher brain functions like thinking and voluntary movements, not for maintaining homeostasis.

Correct Answer: B

Rationale: The correct answer is B (2 ATP molecules produced per FADH2 molecule) in aerobic respiration. FADH2 enters the electron transport chain at a later stage compared to NADH, leading to the production of 2 ATP through oxidative phosphorylation. FADH2 donates electrons to Complex II, bypassing Complex I, resulting in a lower energy yield compared to NADH which donates electrons to Complex I. Choice A (1 ATP) is incorrect as FADH2 produces more ATP than that. Choice C (3 ATP) is incorrect as FADH2 produces 2 ATP, not 3. Choice D (4 ATP) is incorrect as FADH2 produces 2 ATP, not 4.

Correct Answer: C

Rationale: The correct answer is C because not all macromolecules contain phosphorus. Macromolecules such as proteins, carbohydrates, and lipids contain carbon, hydrogen, and oxygen but not necessarily phosphorus. Proteins and carbohydrates can exist as single chains or be branched, so choices A and B are not characteristics that exclude a macromolecule. Choice D is also incorrect because not all macromolecules are used by the body, as some like cellulose are not digestible by humans.

Correct Answer: A

Rationale: The correct answer is A: To transport oxygen and nutrients. The cardiovascular system is responsible for circulating blood throughout the body to deliver oxygen and nutrients to tissues and organs. This function supports cell metabolism and overall body function. Choice B is incorrect because while the cardiovascular system does play a role in blood pressure regulation, it is not its primary function. Choice C is incorrect as digestion is primarily carried out by the digestive system. Choice D is incorrect as waste filtration is mainly performed by the excretory system.