Practice TEAS Science Test

Correct Answer: C

Rationale: The correct answer is C: Nucleus. The nucleus contains the cell's genetic material in the form of DNA, which carries the instructions for the cell's functions and characteristics. This is where processes such as transcription and replication occur. Ribosomes (choice A) are responsible for protein synthesis. Mitochondria (choice B) are the powerhouse of the cell, producing energy. Cytoplasm (choice D) is the fluid that fills the cell and supports organelles, but it does not store genetic information.

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: C

Rationale: The correct answer is C: Large intestine. The large intestine is responsible for absorbing water and forming feces as it reabsorbs water from the indigestible food particles that pass through it, leading to the formation of solid waste (feces). The stomach (A) primarily breaks down food with gastric juices. The small intestine (B) is where most nutrient absorption occurs, not water absorption for feces formation. The esophagus (D) is a muscular tube that carries food from the mouth to the stomach, with no role in water absorption or feces formation.

Correct Answer: D

Rationale: The correct answer is D: Sympathetic nervous system. This system is responsible for activating the 'fight or flight' response in situations of stress or danger. It triggers physiological changes such as increased heart rate, dilation of pupils, and release of adrenaline. The central nervous system (A) includes the brain and spinal cord but doesn't directly control this response. The peripheral nervous system (B) includes nerves outside the brain and spinal cord but doesn't specifically regulate 'fight or flight'. The autonomic nervous system (C) includes both sympathetic and parasympathetic divisions, with the sympathetic division being the one involved in the 'fight or flight' response.

Correct Answer: A

Rationale: Insulin is the correct answer as it helps regulate blood sugar levels by facilitating the uptake of glucose into cells. Adrenaline, cortisol, and melatonin do not directly regulate blood sugar levels like insulin does. Adrenaline primarily affects the fight-or-flight response, cortisol is involved in stress response and metabolism, and melatonin regulates sleep-wake cycles. Insulin's role in blood sugar regulation is crucial for maintaining proper glucose levels in the body.