Correct Answer: B

Rationale: The pineal gland is responsible for maintaining the body's circadian rhythm by producing melatonin. Melatonin is a hormone that helps regulate the sleep-wake cycle and is essential in controlling the body's internal clock. The thyroid gland, although important for metabolism, is not directly involved in regulating circadian rhythms. The pancreas plays a role in blood sugar regulation through insulin production, not in controlling circadian rhythms. The hypothalamus is involved in regulating various bodily functions, but the pineal gland is specifically responsible for the circadian rhythm.

Correct Answer: A

Rationale: The correct answer is A: Ribosome. Ribosomes are the organelles responsible for protein synthesis in the cell. They are the cellular machinery where translation, the process of assembling proteins from amino acids based on mRNA sequences, occurs. Ribosomes can be found floating freely in the cytoplasm or attached to the endoplasmic reticulum. The nucleus (choice B) houses DNA but is not directly involved in protein synthesis. Mitochondria (choice C) are responsible for energy production through cellular respiration, not protein synthesis. The Golgi apparatus (choice D) is involved in modifying, sorting, and packaging proteins for secretion, not in the synthesis of proteins.

Correct Answer: B

Rationale: The primary function of the kidneys is to filter blood and remove waste products from the body, producing urine in the process. This function helps in maintaining the body's internal environment stable, a process known as homeostasis. Option A, 'To digest food,' is incorrect as digestion primarily occurs in the gastrointestinal system, not in the kidneys. Option C, 'To absorb nutrients,' is also incorrect because nutrient absorption mainly takes place in the intestines. Option D, 'To transport oxygen,' is incorrect as the lungs and circulatory system are responsible for oxygen transport, not the kidneys.

Correct Answer: B

Rationale: Ligaments are the correct answer. Ligaments connect bones to other bones, providing stability in joints. Tendons, on the other hand, connect muscles to bones, allowing movement. Cartilage is a type of connective tissue that cushions joints and helps with smooth movements. Muscle tissue is responsible for generating force and movement in the body, not for connecting bones to each other.

Correct Answer: B

Rationale: The correct order of the layers of the epidermis from most superficial to deepest is: Stratum corneum, Stratum lucidum, Stratum granulosum, Stratum spinosum, Stratum basale. Choice B, 'S. corneum, S. lucidum, S. granulosum, S. spinosum, S. basale,' provides the accurate layering from the outermost to the innermost layer of the epidermis. Choice A is incorrect as it starts with Stratum spinosum, which is not the most superficial layer. Choice C is incorrect as it places Stratum spinosum before Stratum basale. Choice D is incorrect as it starts with Stratum basale, which is the deepest layer of the epidermis.