ATI TEAS 7 Science

Correct Answer: B

Rationale: The correct answer is B: Alveoli. Alveoli are tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide occurs during respiration. Oxygen from the air we breathe diffuses into the bloodstream, while carbon dioxide from the blood is released into the alveoli to be exhaled. The trachea (A) is a tube that carries air to and from the lungs, the bronchi (C) are branches of the trachea, and the diaphragm (D) is a muscle that helps with breathing but is not directly involved in gas exchange. Therefore, the alveoli are responsible for gas exchange in the respiratory system.

Correct Answer: D

Rationale: The correct answer is D, Collagen. Collagen is a fibrous protein known for its structural role in connective tissues. It has a triple helix structure, providing strength and support to tissues. Insulin (A) is a hormone, not a fibrous protein. Keratin (B) is a structural protein found in hair and nails. Hemoglobin (C) is a globular protein responsible for oxygen transport in red blood cells. Therefore, collagen is the only fibrous protein among the choices.

Correct Answer: C

Rationale: The correct answer is C: Testes. The testes are responsible for producing testosterone, a male sex hormone. They contain specialized cells called Leydig cells that produce testosterone. The adrenal glands (A) produce hormones like cortisol and adrenaline, not testosterone. The pituitary gland (B) regulates hormone production but does not directly produce testosterone. The pancreas (D) produces insulin and other digestive enzymes, not testosterone. Therefore, the testes are the correct answer for testosterone production.

Correct Answer: B

Rationale: The adrenal glands are responsible for secreting adrenaline and cortisol in response to stress, triggering the fight-or-flight response. Adrenaline increases heart rate and blood flow, while cortisol releases energy stores. The pancreas regulates blood sugar, the thyroid gland controls metabolism, and the pituitary gland regulates hormone production but are not directly involved in the fight-or-flight response.

Correct Answer: A

Rationale: The correct answer is A: Neuron. Neurons are specialized cells that transmit electrical impulses in the nervous system. They consist of a cell body, dendrites to receive signals, an axon to transmit signals, and synaptic terminals to communicate with other neurons. The axon is the long fiber that carries the electrical impulses away from the cell body. Myelin is a fatty substance that insulates and speeds up signal transmission along the axon. Dendrites receive signals from other neurons and transmit them towards the cell body. Therefore, the neuron is the fundamental structure responsible for transmitting electrical impulses, making it the correct answer.