Correct Answer: B

Rationale: The skin is the largest organ in the human body. It serves as a protective barrier against the environment, regulates temperature, and provides sensory information. The liver, brain, and heart are vital organs, but they are not as extensive as the skin. The liver is primarily responsible for detoxification and metabolism. The brain is the control center of the body, coordinating various functions. The heart is a crucial organ that pumps blood throughout the body. However, in terms of size, the skin surpasses all of these organs.

Correct Answer: B

Rationale: Vitamin B12 is the correct answer. It is crucial for the formation and maturation of red blood cells, playing a vital role in preventing megaloblastic anemia. Additionally, Vitamin B12 is essential for maintaining nerve function. Vitamin A is important for vision and immune function, Vitamin C is necessary for collagen synthesis and immune health, and Vitamin D is crucial for bone health and immune function. Therefore, options A, C, and D are incorrect as they do not play a direct role in the formation of red blood cells.

Correct Answer: C

Rationale: The pituitary gland, often referred to as the 'master gland,' controls the release of hormones from other endocrine glands in the body. It secretes various hormones that regulate many bodily functions, making it a central and vital component of the endocrine system. The thyroid gland (Choice A) regulates metabolism, the adrenal gland (Choice B) produces hormones like adrenaline, and the pineal gland (Choice D) secretes melatonin, but none of these glands are considered the 'master gland' that controls the functions of other endocrine glands.

Correct Answer: A

Rationale: The cerebellum is the correct answer. It is responsible for controlling balance, coordination, and fine motor movements. The cerebrum is mainly associated with higher brain functions such as thinking and decision-making, not specifically balance and coordination. The brainstem is responsible for basic life functions like breathing and heartbeat, while the medulla oblongata is involved in regulating autonomic functions like breathing, heart rate, and blood pressure. Therefore, the cerebellum stands out as the key brain region for maintaining physical control and movement.

Correct Answer: B

Rationale: Tendons are the correct answer. They are strong connective tissues that connect muscles to bones, allowing movement when muscles contract. Ligaments connect bones to other bones, providing joint stability. Cartilage is a firm, flexible connective tissue present in joints and the outer ear. Fascia is a connective tissue that surrounds muscles, blood vessels, and nerves, offering support and protection. Therefore, the correct tissue type that connects muscles to bones is tendons.