When does cell death first occur?

Correct Answer: D

Rationale: Cell death, also known as apoptosis, first occurs during fetal development when specific cells are programmed to die. This process is essential for shaping and organizing tissues and organs. Choices A, B, and C are incorrect because cell death begins much earlier, during fetal development, rather than later in life or at puberty. Understanding the timing of cell death in different stages of life is crucial in developmental biology.

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: The correct answer is 'impaired cell division and the ability to break down and recycle worn cell parts.' Aging at the cellular level involves reduced efficiency in cell division and the breakdown/recycling of cellular components, leading to functional decline. Choices A, B, and D are incorrect because they involve external physical manifestations or organ-specific issues rather than cellular-level changes associated with aging.

Correct Answer: D

Rationale: The correct answer is 'never having smoked.' Research suggests that one of the common characteristics among centenarians is that they have never smoked. Smoking is a well-known risk factor for various diseases and can significantly reduce lifespan. Choice A, 'a high level of exercise throughout life,' is not a universal characteristic among centenarians, although exercise can contribute to a healthy lifestyle. Choice B, 'long-lived relatives,' while genetics can play a role in longevity, not all centenarians have long-lived relatives. Choice C, 'following the Mediterranean diet,' is a healthy dietary choice but not a defining characteristic shared by all centenarians.

Correct Answer: D

Rationale: The correct answer is 'sagittal.' A sagittal section divides the body into right and left portions. Choice A, 'frontal,' is incorrect as it divides the body into front and back portions. Choice B, 'transverse,' divides the body into upper and lower portions. Choice C, 'coronal,' divides the body into anterior and posterior portions. Therefore, 'sagittal' is the most appropriate term for a section separating the body into right and left portions.