What is the function of parathyroid hormone?

Correct Answer: D

Rationale: The correct answer is D. Parathyroid hormone plays a crucial role in activating vitamin D. This activation occurs in the kidneys, where parathyroid hormone stimulates the conversion of inactive vitamin D to its active form. Active vitamin D is essential for maintaining proper levels of calcium and phosphorus in the body, which are important for bone health and other physiological functions. Choices A, B, and C are incorrect because parathyroid hormone is not involved in increasing energy levels, stimulating cell reproduction, or speeding up metabolism. Its primary function is related to calcium and phosphorus homeostasis through the activation of vitamin D.

Correct Answer: B

Rationale: Normal values for pulse rate typically range between 60 to 100 beats per minute, while normal blood pressure values are usually around 120/80 mm Hg. Option B falls within these normal ranges for both pulse rate and blood pressure, making it the correct choice. Choices A, C, and D have either pulse rate, blood pressure, or both values outside the normal ranges, making them incorrect.

Correct Answer: A

Rationale: A sagittal section divides the body into right and left regions. This type of section runs longitudinally from front to back, separating the body into right and left halves. Sagittal sections are crucial for understanding the anatomical structure and orientation of various body parts. Choices B, C, and D are incorrect because a sagittal section specifically divides the body into right and left portions, not upper and lower regions, front and back regions, or between the dorsal and ventral cavities.

Correct Answer: A

Rationale: Pepsin is an enzyme produced in the stomach that is essential for breaking down proteins during digestion. It functions by breaking down large protein molecules into smaller peptides, which are further broken down into amino acids for absorption in the intestines. Therefore, option A, 'To break down proteins,' is the correct answer. Choices B, C, and D are incorrect as they do not align with the specific function of pepsin in the body.

Correct Answer: B

Rationale: The esophagus is part of the digestive system. It is a muscular tube that connects the mouth to the stomach, allowing the passage of food and liquids from the mouth to the stomach for digestion. The esophagus plays a crucial role in the process of swallowing and digestion, which are essential functions of the digestive system. Choices A, C, and D are incorrect because the esophagus is not associated with the endocrine, respiratory, or nervous systems.