Vacuoles are large sacs for storage in plant cells. What is their main function in animal cells?

Correct Answer: B

Rationale: Vacuoles in animal cells primarily function in waste storage and disposal, helping to maintain cellular homeostasis by storing waste products and aiding in their removal from the cell. Unlike plant cells, animal cells do not typically use vacuoles for storage purposes such as water, nutrients, or pigments. Instead, animal cells rely on other organelles like lysosomes for waste management and maintaining cellular balance. Choices A, C, and D are incorrect because protein synthesis occurs in ribosomes, photosynthesis takes place in chloroplasts (absent in animal cells), and cellular respiration mainly occurs in mitochondria, respectively. Vacuoles in animal cells serve a different purpose compared to plant cells.

Correct Answer: C

Rationale: The primary function of hematopoietic tissue is the production of blood cells. Hematopoietic tissue, primarily found in the bone marrow, is responsible for generating red blood cells, white blood cells, and platelets. These blood cells are vital for oxygen transport, immune response, and blood clotting. Choices A, B, and D are incorrect as they do not reflect the main function of hematopoietic tissue. Building and repairing bone is primarily carried out by osteoblasts and osteoclasts, supporting and connecting tissues is a role of connective tissues like tendons and ligaments, and contracting for movement is a function of muscle tissue.

Correct Answer: C

Rationale: Stretch marks occur when the dermis layer tears due to rapid stretching of the skin. This tearing leads to the appearance of stretch marks, which are often red or purple at first and then fade to a silvery-white color over time. Inflammation of the dermis or clogging of sebaceous glands are not directly related to the formation of stretch marks. Therefore, choices A, B, and D are incorrect as they do not describe the actual cause of stretch marks.

Correct Answer: A

Rationale: The correct answer is A, Folliculitis. Folliculitis is the medical term for the inflammation of hair follicles, which can be caused by ingrown hairs. Hirsutism refers to excessive hair growth, pseudofolliculitis barbae is a condition where shaving causes ingrown hairs, and alopecia is hair loss. Therefore, choices B, C, and D are incorrect as they do not specifically refer to ingrown hairs.

Correct Answer: C

Rationale: Vitamin D is essential for calcium absorption in the intestines, which is crucial for maintaining strong and healthy bones. Without adequate vitamin D, the body cannot effectively absorb calcium, leading to weakened bones and an increased risk of fractures. Vitamin A (Choice A) is important for vision and immune function but is not directly involved in calcium absorption or bone health. Vitamin C (Choice B) is essential for collagen synthesis and immune function, but it does not play a direct role in calcium absorption or bone health. Vitamin E (Choice D) acts as an antioxidant and helps protect cells from damage, but it is not specifically required for calcium absorption or bone health. Therefore, the correct answer is Vitamin D as it is crucial for optimal bone health.