1. The human immunodeficiency virus (HIV) targets and destroys which type of immune cell?

A. Neutrophils
B. Macrophages
C. Helper T cells
D. Memory B cells

Correct answer: A

Rationale: The correct answer is C: Helper T cells. HIV targets and destroys Helper T cells, which are a crucial component of the immune system responsible for coordinating the immune response. Neutrophils and macrophages are also important immune cells, but they are not the primary target of HIV. Memory B cells are responsible for mounting a rapid response upon re-exposure to a pathogen but are not the main target of HIV. Thus, HIV primarily affects Helper T cells, leading to the weakening of the immune system and the development of acquired immunodeficiency syndrome (AIDS).

2. What can be inferred about the water management systems in Petra?

A. They were unreliable and contributed to the city's decline.
B. They were simple and ineffective compared to modern systems.
C. They were sophisticated and played a crucial role in Petra's survival.
D. They were destroyed by explorers when Petra was rediscovered.

Correct answer: C

Rationale: The passage highlights the "elaborate" water systems, suggesting their complexity and importance.

3. What is the term for the shedding of the outermost layer of the epidermis?

A. Desquamation
B. Exfoliation
C. Keratinization
D. Epidermolysis

Correct answer: A

Rationale: The correct term for the shedding of the outermost layer of the epidermis is desquamation. Desquamation is a natural process where old skin cells are shed off to make way for new cells. Exfoliation refers to the removal of dead skin cells through external means like scrubs. Keratinization is the process by which skin cells produce the protein keratin, while epidermolysis is a condition where the epidermis separates from the dermis. Therefore, in this context, desquamation is the most appropriate term for the shedding of the outermost layer of the epidermis.

4. Which of the following is NOT a greenhouse gas?

A. Carbon dioxide
B. Water vapor
C. Nitrogen
D. Methane

Correct answer: C

Rationale: Rationale: A) Carbon dioxide: Carbon dioxide is a greenhouse gas that is naturally present in the Earth's atmosphere and is also released through human activities such as burning fossil fuels. B) Water vapor: Water vapor is a greenhouse gas that is naturally present in the atmosphere and plays a significant role in the Earth's climate system. C) Nitrogen: Nitrogen is not considered a greenhouse gas because it does not have the ability to absorb and emit infrared radiation in the same way that greenhouse gases like carbon dioxide and methane do. D) Methane: Methane is a potent greenhouse gas that is released through natural processes such as wetland decomposition and human activities such as livestock farming and fossil fuel extraction. Therefore, the correct answer is C) Nitrogen, as it is not a greenhouse gas.

5. Bile, a digestive juice, is produced by which organ?

A. Stomach
B. Liver
C. Pancreas
D. Small intestine

Correct answer: B

Rationale: The correct answer is B: Liver. Bile is a digestive juice that is produced by the liver and stored in the gallbladder. It plays a crucial role in the digestion and absorption of fats in the small intestine. The stomach primarily produces gastric juices that aid in breaking down food, while the pancreas secretes digestive enzymes and bicarbonate into the small intestine. The small intestine is responsible for the absorption of nutrients. Therefore, the liver is the organ that produces bile, making it the correct answer to this question.