1. The liver plays a vital role in digestion. What is one of the main functions of the liver in the digestive system?

A. Physical breakdown of food
B. Production of digestive enzymes
C. Storage and processing of nutrients
D. Elimination of waste products

Correct answer: C

Rationale: The correct answer is C: 'Storage and processing of nutrients.' The liver is a crucial organ in the digestive system as it performs various functions such as storing nutrients like glucose, vitamins, and minerals, processing nutrients by converting them into usable forms for the body, and regulating their distribution to different parts of the body. While the physical breakdown of food primarily occurs in the mouth and stomach, and the production of digestive enzymes mainly happens in the pancreas and small intestine, the liver's main role is to manage and store the nutrients obtained from the digested food. Therefore, option C is the correct choice for the main function of the liver in the digestive process.

2. The feedback loop is a crucial concept in endocrine regulation. In a negative feedback loop, high levels of a hormone can:

A. Further stimulate the release of the same hormone
B. Inhibit the release of the hormone or its production
C. Have no effect on the hormone's regulation
D. Increase the need for another hormone entirely

Correct answer: B

Rationale: In a negative feedback loop, high levels of a hormone signal the body to stop producing more of that hormone in order to maintain homeostasis. This is a self-regulating mechanism to prevent excessive levels of the hormone. Option B is correct because in this scenario, the high levels of the hormone will inhibit its further release or production. This feedback loop helps ensure that hormone levels stay within a narrow range, preventing overstimulation or imbalance in the endocrine system. Options A, C, and D are incorrect as they do not align with the concept of negative feedback regulation in endocrine systems.

3. A ball is thrown upwards. Which of the following statements is TRUE about its potential energy and kinetic energy at the peak of its trajectory?

A. Both potential and kinetic energy are zero.
B. Potential energy is maximum and kinetic energy is minimum.
C. Potential energy is minimum and kinetic energy is maximum.
D. Both potential and kinetic energy remain constant.

Correct answer: B

Rationale: At the peak, the ball momentarily stops moving, minimizing kinetic energy. However, it's still at its highest point, maximizing its potential energy due to gravity.

4. What is the name for the tiny particles that make up atoms?

A. Protons
B. Electrons
C. Neutrons
D. Subatomic particles

Correct answer: D

Rationale: Protons, neutrons, and electrons are all subatomic particles that make up atoms.

5. What property of matter refers to the amount of space occupied by an object?

A. Mass
B. Volume
C. Weight
D. Density

Correct answer: b

Rationale: Volume measures the amount of space occupied by an object.

6. What happens when a protein unfolds?

A. Activation
B. Denaturation
C. Renaturation
D. Folding

Correct answer: B

Rationale: Rationale: - Activation (Option A) refers to the process of initiating or increasing the activity of a molecule, such as an enzyme. Protein unfolding does not involve activation. - Denaturation (Option B) is the correct answer. Denaturation refers to the process by which a protein loses its three-dimensional structure, leading to the disruption of its function. This can be caused by factors such as heat, pH changes, or chemicals. - Renaturation (Option C) is the process by which a denatured protein regains its native structure and function. Protein unfolding is the opposite of renaturation. - Folding (Option D) is the process by which a protein assumes its functional three-dimensional structure. Unfolding is the reverse process of folding, not folding itself.