1. Which vitamin is essential for calcium absorption and bone health?

A. Vitamin A
B. Vitamin C
C. Vitamin D
D. Vitamin E

Correct answer: C

Rationale: The correct answer is Vitamin D. Vitamin D plays a crucial role in calcium absorption in the intestines, which is essential for maintaining strong and healthy bones. It helps regulate calcium and phosphorus levels in the body, promoting bone mineralization and growth. Vitamin A is important for vision and immune function, not specifically for bone health. Vitamin C is essential for collagen synthesis but not directly involved in calcium absorption. Vitamin E is an antioxidant that protects cells from damage but does not have a direct role in bone health. Therefore, Vitamin D is the correct choice for supporting calcium absorption and bone health.

2. What is the purpose of the spindle apparatus in cell division?

A. To separate sister chromatids
B. To move chromosomes to opposite poles of the cell
C. To form a new nuclear envelope around each daughter cell
D. To synthesize new DNA

Correct answer: B

Rationale: Rationale: The spindle apparatus is a structure composed of microtubules that plays a crucial role in cell division (mitosis and meiosis). Its main purpose is to ensure the proper separation and distribution of chromosomes to opposite poles of the cell during cell division. This process is essential for the formation of two genetically identical daughter cells in mitosis or four haploid daughter cells in meiosis. Option A is incorrect because the separation of sister chromatids specifically refers to the role of the kinetochore fibers within the spindle apparatus. Option C is incorrect because the formation of a new nuclear envelope occurs after the chromosomes have been properly segregated. Option D is incorrect because DNA synthesis does not occur within the spindle apparatus; it takes place during the S phase of the cell cycle.

3. Which hormone, produced by the pituitary gland, stimulates the production of milk in mammary glands during breastfeeding?

A. Growth hormone (GH)
B. Thyroid-stimulating hormone (TSH)
C. Prolactin
D. Follicle-stimulating hormone (FSH)

Correct answer: c

Rationale: The correct answer is C: Prolactin. Prolactin is the hormone produced by the pituitary gland that stimulates the production of milk in the mammary glands during breastfeeding. It plays a crucial role in lactation by promoting the growth and development of the mammary glands and initiating the production of milk. Growth hormone (GH) regulates growth and metabolism, not milk production. Thyroid-stimulating hormone (TSH) stimulates the thyroid gland, not mammary glands. Follicle-stimulating hormone (FSH) is involved in reproductive processes, not milk production. Therefore, prolactin is the hormone directly responsible for stimulating milk production during breastfeeding.

4. Which type of muscle tissue is found in the walls of blood vessels and helps regulate blood flow?

A. Skeletal muscle
B. Smooth muscle
C. Cardiac muscle
D. Striated muscle

Correct answer: B

Rationale: The correct answer is B: Smooth muscle. Smooth muscle is found in the walls of blood vessels and plays a crucial role in regulating blood flow by contracting and relaxing to adjust the diameter of the blood vessels. Skeletal muscle (option A) is responsible for movement of the body, cardiac muscle (option C) is found in the heart and responsible for pumping blood, and striated muscle (option D) refers to both skeletal and cardiac muscle due to their striated appearance. Therefore, the specific type of muscle tissue in blood vessel walls is smooth muscle.

5. The element with the atomic number 17 is:

A. Chlorine (Cl)
B. Nitrogen (N)
C. Sodium (Na)
D. Fluorine (F)

Correct answer: A

Rationale: Chlorine (Cl) - Chlorine has 17 protons, corresponding to atomic number 17.

6. The main function of the large intestine is:

A. Digesting and absorbing nutrients
B. Storing and mixing food
C. Breaking down carbohydrates
D. Absorbing water and electrolytes

Correct answer: D

Rationale: The correct answer is D: Absorbing water and electrolytes. The main function of the large intestine is to absorb any remaining water and electrolytes from the indigestible food matter that passes through it. This absorption process helps in forming solid waste (feces) and regulating the body's fluid balance. It is not primarily responsible for digesting and absorbing nutrients like the small intestine, storing and mixing food like the stomach, or breaking down carbohydrates. Understanding the role of the large intestine in water and electrolyte absorption is crucial for maintaining proper digestion and overall health.