What is the primary function of the lymphatic system?

Correct Answer: C

Rationale: The correct answer is C: 'To fight infection and remove excess fluid.' The lymphatic system plays a crucial role in the body's immune response by fighting infections through lymphocytes and removing excess fluid from tissues, maintaining fluid balance. It does not primarily transport oxygen, filter blood, or transport hormones. While the lymphatic system is involved in lipid absorption and transport, its primary functions are related to immunity and fluid balance.

Correct Answer: A

Rationale: The correct answer is A: Neuron. Neurons are specialized cells that transmit electrical impulses in the nervous system. While the axon is the part responsible for conducting these impulses over long distances, it is the neuron as a whole that is ultimately responsible for transmitting electrical impulses. Myelin is a fatty substance that surrounds and insulates axons, speeding up signal transmission. Dendrites, on the other hand, receive signals from other neurons. Therefore, although the axon plays a significant role in transmission, the neuron is the fundamental unit responsible for transmitting electrical impulses in the nervous system.

Correct Answer: B

Rationale: The correct answer is B: 'To regulate hormones.' The hypothalamus plays a crucial role in regulating hormones and maintaining homeostasis by controlling various functions such as hunger, thirst, body temperature, and sleep-wake cycles. While digestion, body temperature, and the immune system are important bodily functions, they are not primarily controlled by the hypothalamus. Therefore, choices A, C, and D are incorrect as they do not accurately represent the primary function of the hypothalamus.

Correct Answer: A

Rationale: The correct answer is the Hypothalamus. The hypothalamus plays a crucial role in regulating body temperature, hunger, thirst, and maintaining overall homeostasis in the body. It receives input from temperature receptors in the skin and internal organs and helps initiate responses to maintain a stable internal body temperature. Acting as the body's thermostat, the hypothalamus adjusts responses to ensure the body's temperature remains within a narrow range, despite external conditions. The Cerebellum (Choice B) is primarily involved in coordinating movement and balance, not regulating body temperature. The Pituitary gland (Choice C) is responsible for producing and secreting hormones that regulate various bodily functions but not directly involved in body temperature regulation. The Thyroid gland (Choice D) plays a role in metabolism and hormone regulation but is not the primary regulator of body temperature.

Correct Answer: A

Rationale: The correct answer is A: 'To break down food into nutrients.' The primary function of the digestive system is to break down food into nutrients that can be absorbed by the body for energy, growth, and repair. The digestive system is not responsible for absorbing oxygen (Choice B), as that is the role of the respiratory system. While the digestion process does release energy from nutrients, the primary function is not to produce energy (Choice C), but rather to extract nutrients for energy production. Regulating body temperature (Choice D) is primarily handled by the thermoregulatory mechanisms in the body, such as the skin and sweat glands, not the digestive system.