What condition might result from a lack of vitamin C?

Correct Answer: D

Rationale: Scurvy is the correct answer. Scurvy is a condition caused by a deficiency of vitamin C in the diet. Vitamin C is essential for collagen synthesis, and its deficiency leads to symptoms such as weakness, swollen and bleeding gums, joint pain, fatigue, and easy bruising. If left untreated, scurvy can lead to more severe complications. Choices A, B, and C are incorrect. Kwashiorkor is a severe form of malnutrition due to insufficient protein intake, pellagra is caused by a deficiency of niacin (vitamin B3), and rickets results from a deficiency of vitamin D, calcium, or phosphate.

Correct Answer: C

Rationale: The correct answer is 'C: anterior.' The term 'anterior' refers to a position in front of or toward the front of the body. In this case, the ribs are positioned in front of the lungs when considering the anatomical position. The term 'medial' means toward the midline of the body, 'superior' means above or higher in position, and 'deep' refers to a position farther from the surface or external part. Therefore, the most appropriate choice is 'anterior' when describing the relationship between the ribs and the lungs.

Correct Answer: D

Rationale: Lactase is the enzyme responsible for breaking down lactose, a sugar present in milk and dairy products. When lactase breaks down lactose, it splits it into two simpler sugars, glucose, and galactose, which can then be absorbed and used by the body. Catalase is involved in breaking down hydrogen peroxide into water and oxygen. Lipase breaks down fats into fatty acids and glycerol. Protease breaks down proteins into amino acids. Therefore, choices A, B, and C are incorrect for the specific breakdown of lactose.

Correct Answer: D

Rationale: The correct answer is D: 'It supplies blood to the heart muscle.' The coronary artery's main function is to supply oxygenated blood to the heart muscle, ensuring that the heart receives the necessary nutrients and oxygen it needs to function properly. Choices A, B, and C are incorrect because the coronary artery specifically delivers oxygenated blood to the heart muscle, not deoxygenated blood to the lungs or blood to the rest of the body.

Correct Answer: D

Rationale: The upper respiratory tract includes structures such as the nose, nasal cavity, pharynx, and larynx. These structures are responsible for filtering, warming, and humidifying the air. The lower respiratory tract comprises the trachea, bronchi, bronchioles, alveolar ducts, and alveoli. Bronchioles, alveolar ducts, and alveoli are all part of the lower respiratory system, involved in gas exchange. Therefore, the correct answer is 'None of the above' as none of the listed options are part of the upper respiratory tract.

Correct Answer: D

Rationale: The correct answer is D, the radius. The axial skeleton comprises bones located along the central axis of the body. It includes the skull, ribs, breastbone (sternum), vertebrae, and sacrum. The radius, on the other hand, is a bone of the forearm, part of the appendicular skeleton. The appendicular skeleton consists of the bones of the limbs and their girdles, not the central axial bones.

Correct Answer: C

Rationale: The gall bladder is part of the digestive system. Its primary function is to store and concentrate bile produced by the liver and release it into the small intestine to aid in the digestion of fats. This process facilitates the breakdown and absorption of fats from the food we consume. Choices A, B, and D are incorrect as the gall bladder is not associated with the endocrine, urinary, or nervous systems.

Correct Answer: A

Rationale: Hormones are signaling molecules produced by glands in multicellular organisms. They travel through the bloodstream to specific target cells where they regulate various physiological processes, including growth, differentiation, and metabolism. Neurons (choice B) are nerve cells that transmit nerve impulses and are not responsible for controlling growth, differentiation, or metabolism. Glands (choice C) produce and release hormones but are not the chemical messengers themselves. Second messengers (choice D) are molecules involved in intracellular signal transduction, not the primary chemical messengers controlling growth, differentiation, and metabolism. Therefore, hormones (choice A) are the correct answer as they match the description provided in the question.

Correct Answer: D

Rationale: Progesterone initiates the preparation of the endometrium of the uterus for pregnancy. It promotes the growth of blood vessels and glands in the endometrial lining, making it conducive for implantation and supporting early pregnancy. While estrogen helps in thickening the endometrium, it is progesterone that plays a crucial role in preparing it for pregnancy. FSH (Follicle-stimulating hormone) is involved in stimulating ovarian follicles, not directly in preparing the endometrium. LH (Luteinizing hormone) triggers ovulation but does not primarily prepare the endometrium for pregnancy.