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: Vitamin D. When skin is exposed to sunlight, it triggers the production of Vitamin D in the body. Sunlight activates a form of cholesterol in the skin, which then converts to Vitamin D through a series of chemical reactions. Vitamin A (Choice A) is not produced by sunlight but is found in foods like carrots. Vitamin K (Choice C) is involved in blood clotting and bone health but is not produced by sunlight. Vitamin E (Choice D) is an antioxidant found in foods like nuts and seeds, not produced through sun exposure.

Correct Answer: D

Rationale: The correct answer is D: All of the above. The large intestine plays a crucial role in absorbing water to form solid waste (A). It also houses beneficial bacteria that produce vitamin K, essential for blood clotting and bone health (B). Additionally, the large intestine is involved in the absorption of some vitamin B compounds produced by gut bacteria (C). Thus, all the functions listed (A, B, C) are carried out by the large intestine. Other choices are incorrect because they do not encompass all the functions performed by the large intestine.

Correct Answer: B

Rationale: The correct answer is B: Medulla oblongata. This part of the brain is located in the brainstem and is responsible for regulating essential involuntary functions such as breathing, heart rate, and blood pressure. It contains vital centers that control these functions, making it the correct choice. Rationale: 1. Cerebrum (A): The cerebrum is responsible for higher brain functions such as thinking, memory, and voluntary movements. It does not directly control involuntary functions like breathing and heart rate. 2. Cerebellum (C): The cerebellum is involved in coordination, balance, and muscle movement but does not regulate involuntary functions like breathing and heart rate. 3. Thalamus (D): The thalamus acts as a relay center for sensory information but is not primarily involved in controlling involuntary functions like breathing and heart rate. In summary, the Medulla oblongata is the correct answer because it specifically houses the centers that control vital involuntary functions, distinguishing

Correct Answer: B

Rationale: The correct answer is B: Jejunum. The jejunum is the primary site of absorption in the small intestine due to its extensive surface area, presence of villi and microvilli that increase absorption capacity, and higher blood supply compared to other regions. It is where most nutrients such as carbohydrates, proteins, and fats are absorbed. The duodenum (A) is mainly responsible for initial digestion, the ileum (C) absorbs bile salts, vitamin B12, and some nutrients, and the cecum (D) is part of the large intestine and is not involved in nutrient absorption.