What is the primary function of antibodies?

Correct Answer: D

Rationale: The correct answer is D: Facilitate the breakdown of antigens. Antibodies are protein molecules produced by the immune system in response to the presence of foreign substances, known as antigens, in the body. Antibodies bind to specific antigens and mark them for destruction by other immune cells, thereby helping the body to defend against infections and other threats. Choices A, B, and C are incorrect because antibodies do not have a direct role in the production of white blood cells, initiation of gluconeogenesis, or promotion of intracellular storage of lipids. The primary function of antibodies is to target and facilitate the destruction of antigens in the body.

Correct Answer: B

Rationale: The correct answer is B: Walking. Walking is not directly controlled by the autonomic nervous system. Walking is a voluntary action governed by the somatic nervous system, which controls voluntary skeletal muscle movement. The autonomic nervous system, on the other hand, regulates functions that are involuntary, such as digestion, heartbeat, and temperature regulation. Choices A, C, and D are all functions controlled by the autonomic nervous system. Digestion involves processes like peristalsis and secretion of digestive enzymes, heartbeat is regulated by the autonomic nervous system to maintain blood pressure and circulation, and temperature regulation includes responses like sweating or shivering to maintain body temperature within a narrow range.

Correct Answer: B

Rationale: The possible conclusion that can be drawn from every child in a certain family suffering from autism is that autism may be genetic. The fact that every child in the family has autism suggests a strong genetic influence on the condition within this particular family. This does not necessarily mean that autism is solely genetic in all cases, but in this specific family, the pattern of all children being affected points towards a genetic connection. Choice A is incorrect as the information provided does not suggest that autism is lethal. Choice C is incorrect as there is no evidence to support a relationship between autism and traditional nuclear family structures. Choice D is incorrect because a conclusion can be drawn from the given evidence, indicating a potential genetic link within this specific family.

Correct Answer: B

Rationale: Bartholin's glands are two small glands located on each side of the vaginal opening. Their primary function is to secrete fluids that help lubricate the vagina during sexual arousal. This lubrication helps to reduce friction and discomfort during sexual activity, making intercourse more comfortable and pleasurable. Choices A, C, and D are incorrect because Bartholin's glands do not secrete hormones to respond to stress, control growth and development, or stimulate the development of T cells. Their main role is specifically related to vaginal lubrication.

Correct Answer: D

Rationale: Mildly elevated levels of thyroxine will increase the heart rate. Thyroxine, a hormone produced by the thyroid gland, regulates metabolism. Elevated thyroxine levels can lead to increased metabolism, resulting in an elevated heart rate. Choice A is incorrect as mildly elevated thyroxine levels do not stop the heart rate. Choice B is incorrect because elevated thyroxine levels do have an effect on heart rate. Choice C is incorrect as elevated thyroxine levels typically lead to an increase rather than a decrease in heart rate.