1. What is the term for the involuntary muscle contractions that move food through the digestive tract?

A. Segmentation
B. Peristalsis
C. Chyme
D. Emulsification

Correct answer: B

Rationale: The correct answer is B: Peristalsis. Peristalsis is the term used to describe the involuntary muscle contractions that help move food through the digestive tract. These rhythmic contractions occur in the smooth muscles of the digestive system and help propel food and other substances like chyme through the esophagus, stomach, and intestines. Segmentation, choice A, refers to the mixing movements in the intestines that aid in digestion but do not move food along the tract. Chyme, choice C, is the semi-fluid mass of partially digested food that moves from the stomach to the small intestine. Emulsification, choice D, is the process of breaking down fats into smaller droplets to aid in digestion, but it is not directly related to the movement of food through the digestive tract.

2. An IV bag contains 500ml of saline solution and needs to be infused over 4 hours. What is the flow rate in drops per minute, assuming 20 drops per milliliter?

A. 12.5 drops/min
B. 25 drops/min
C. 50 drops/min
D. 100 drops/min

Correct answer: C

Rationale: Calculate the total volume in drops (500ml * 20 drops/ml = 10,000 drops). Divide this by the infusion time in minutes (4 hours * 60 minutes/hour = 240 minutes) to get the flow rate.

3. Which organelle is responsible for controlling the activities of the cell?

A. Golgi apparatus
B. Mitochondria
C. Nucleus
D. Ribosomes

Correct answer: C

Rationale: Rationale: The nucleus is the organelle responsible for controlling the activities of the cell. It contains the cell's genetic material (DNA) and serves as the command center of the cell, regulating gene expression and directing cellular activities. The nucleus plays a crucial role in cell growth, metabolism, and reproduction. The Golgi apparatus is involved in processing and packaging proteins, the mitochondria are responsible for producing energy in the form of ATP, and ribosomes are involved in protein synthesis. However, none of these organelles have the primary function of controlling the activities of the cell like the nucleus does.

4. What is the function of arrector pili muscles?

A. To control sweat production
B. To contract and cause goosebumps
C. To produce sebum
D. To sense touch

Correct answer: B

Rationale: The correct answer is B: 'To contract and cause goosebumps.' Arrector pili muscles are small muscles attached to hair follicles in the skin. When these muscles contract, they cause the hair to stand upright, resulting in the appearance of goosebumps. This physiological response is a remnant of our evolutionary past when our ancestors had more hair, and the raised hair helped to trap air for insulation or to make them look larger when threatened. Therefore, the function of arrector pili muscles is not to control sweat production (A), produce sebum (C), or sense touch (D), but rather to create the physical response of goosebumps.

5. During gas exchange in the alveoli, what happens to oxygen?

A. Oxygen is released from the bloodstream into the alveoli.
B. Oxygen is absorbed from the alveoli into the bloodstream.
C. Oxygen is converted into carbon dioxide.
D. Oxygen is stored in the alveoli for later use.

Correct answer: B

Rationale: During gas exchange in the alveoli, oxygen is absorbed from the alveoli into the bloodstream. In the alveoli, oxygen diffuses across the thin walls of the alveoli and into the surrounding capillaries where it binds to hemoglobin in red blood cells. This oxygen-rich blood is then transported to the body's tissues for cellular respiration. Therefore, option B is correct as it accurately describes the direction of oxygen movement during the process of gas exchange in the lungs.