TEAS 7 Science Practice Test

Correct Answer: A

Rationale: The correct answer is A: capillaries. Capillaries are tiny blood vessels where the exchange of oxygen and nutrients occurs between the blood and tissues through diffusion. Capillaries have thin walls to facilitate the exchange process efficiently. Veins carry blood back to the heart, ventricles are chambers of the heart, and arteries carry blood away from the heart. Thus, they are not sites for oxygen exchange between blood and tissues.

Correct Answer: C

Rationale: The correct answer is C: At the center of the brain hemispheres. The pineal gland is located in the brain, specifically at the center of the brain hemispheres. It is a small endocrine gland responsible for secreting melatonin, a hormone that regulates sleep-wake cycles. Choices A, B, and D are incorrect because the pineal gland is not located below the larynx, above the kidney, or at the base of the brain. The pineal gland's location in the center of the brain makes it unique and vital for regulating various physiological functions.

Correct Answer: C

Rationale: The correct answer is C: enamel. Enamel is a tissue layer found in teeth, not in skeletal bone. A: Periosteum is a dense layer of connective tissue covering the bone. B: Bone marrow is found inside bones and is responsible for blood cell production. D: Cancellous bone is a spongy, porous bone tissue found at the ends of long bones. Enamel is a hard, outer layer of the tooth, not a tissue layer in skeletal bone.

Correct Answer: D

Rationale: The correct answer is D: cytotoxic T cells. These cells are a type of white blood cell that plays a key role in adaptive immunity by identifying and destroying infected cells. Step 1: Cytotoxic T cells recognize specific antigens on infected cells. Step 2: They release cytotoxic chemicals to destroy the infected cells. Step 3: This process helps eliminate pathogens and infected cells from the body. Memory B cells (A) are responsible for producing antibodies upon re-exposure to a pathogen, not directly attacking pathogens. Neutrophils (B) are phagocytic cells that engulf pathogens but are not specific to adaptive immunity. Antibodies (C) are proteins produced by B cells that bind to pathogens to facilitate their destruction but do not directly attack pathogens like cytotoxic T cells.

Correct Answer: C

Rationale: The correct answer is C: hypodermis. The hypodermis is the deepest layer of the skin and acts as an energy reserve by storing adipocytes (fat cells) that can be used for energy when needed. Adipocytes in the hypodermis help to insulate the body and provide cushioning. The epidermis (A) is the outermost layer of the skin that provides protection. The dermis (B) is the middle layer that contains blood vessels, nerves, and hair follicles. The stratum basale (D) is the bottom layer of the epidermis where new skin cells are produced. Therefore, the hypodermis is the correct answer as it specifically functions as an energy reserve through storing adipocytes.