Correct Answer: A

Rationale: Assimilation is the process of changing absorbed substances into different chemical forms. It occurs after nutrients from food are absorbed into the bloodstream and used by the body. Choice B, breaking down foods into nutrients that the body can absorb, refers to the process of digestion rather than assimilation. Choice C, eliminating waste from the body, describes the process of excretion. Choice D, an increase in body size without a change in overall shape, does not accurately define assimilation.

Correct Answer: C

Rationale: Wrinkled and sagging skin is primarily caused by the loss of subcutaneous fat and reduced levels of elastin and collagen in the skin. Choice A is incorrect as drinking too much water does not lead to wrinkled and sagging skin. Choice B is incorrect because heredity alone does not cause this condition. Excess subcutaneous fat, as mentioned in Choice D, can contribute to a different skin appearance, such as puffiness, but not wrinkled and sagging skin.

Correct Answer: C

Rationale: Ultrasonography is a medical imaging technique that uses sound waves to visualize internal body structures. It is particularly effective for examining soft tissues like organs, blood vessels, and fetuses. Choice A is incorrect because bones are better visualized using techniques like X-rays. Choice B is incorrect as air-filled organs like lungs are not well visualized with ultrasound due to air being a poor conductor of sound waves. Choice D is incorrect since ultrasonography cannot visualize structures at a microscopic level, as it is used for larger internal structures.

Correct Answer: A

Rationale: The statement is true. The field of medicine evolved as early healers moved away from superstition and magic, instead focusing on natural chemicals to treat illnesses. This transition marked a shift towards a more scientific and evidence-based approach to healthcare. Choice B is incorrect because the statement accurately reflects the historical development of medicine. Choice C is incorrect as the historical transition from superstition to natural chemicals is a well-documented aspect of the evolution of medicine. Choice D is incorrect as the statement provided is true.

Correct Answer: B

Rationale: Chromosomes do not get longer as a cell ages. In fact, chromosomes condense and become more compact during cell division to ensure proper segregation. Choice A is incorrect because chromosomes do not elongate with age. Choice C is not the correct answer as there is scientific evidence to support that chromosomes do not lengthen over time. Choice D is not the right option as the correct answer is 'False' in this case.