1. Immunoglobulin G (IgG) is the most abundant antibody type, responsible for:

A. Immediate allergic reactions
B. Neutralizing toxins and viruses
C. Activating other immune cells
D. Protecting newborns from infections

Correct answer: B

Rationale: The correct answer is B: 'Neutralizing toxins and viruses.' Immunoglobulin G (IgG) is the most abundant antibody type in the blood and tissues. It plays a crucial role in neutralizing toxins and viruses by binding to them and marking them for destruction by other immune cells. IgG is also involved in opsonization, which enhances phagocytosis of pathogens by immune cells. While IgE is primarily responsible for immediate allergic reactions, IgG's main functions are related to immunity against pathogens rather than allergic responses. Activating other immune cells is typically associated with antibodies like IgM, while protecting newborns from infections is mainly attributed to maternal IgG antibodies passed on during pregnancy. Therefore, option B is the most accurate description of IgG's role in the immune system.

2. Myelin sheath is a fatty substance that insulates and protects the long extensions of some nerve cells. It is produced by:

A. Schwann cells
B. Astrocytes
C. Neurons
D. Oligodendrocytes

Correct answer: A

Rationale: The correct answer is A: Schwann cells. Schwann cells are a type of glial cell in the peripheral nervous system that produce the myelin sheath around axons. Myelin sheath is essential for the rapid conduction of nerve impulses and provides insulation and protection to nerve fibers. Astrocytes are glial cells that provide support and maintain homeostasis in the central nervous system, but they do not produce myelin. Neurons are the main functional units of the nervous system responsible for transmitting nerve impulses. Oligodendrocytes are another type of glial cell in the central nervous system that produce myelin sheath around axons in that region, not in the peripheral nervous system where Schwann cells are responsible for myelination.

3. hich word is most closely associated with the adjective "meticulous"?

A. careless
B. precise
C. indifferent
D. enthusiastic

Correct answer: B

Rationale: "Meticulous" implies carefulness and attention to detail, making "precise" its closest synonym.

4. When sodium hydroxide (NaOH) reacts with hydrochloric acid (HCl), the resulting product is:

A. Hydrogen gas and sodium chloride (NaCl)
B. Chlorine gas and sodium oxide (Na2O)
C. Sodium metal (Na) and water (H2O)
D. No reaction occurs.

Correct answer: A

Rationale: This is a classic neutralization reaction, forming water and a salt (sodium chloride).

5. Insulin, a hormone responsible for regulating blood sugar levels, is produced by the:

A. Parathyroid gland
B. Pancreas
C. Thymus gland
D. Ovaries

Correct answer: B

Rationale: The correct answer is B: Pancreas. Insulin is a hormone that plays a crucial role in regulating blood sugar levels by allowing cells to take in glucose from the bloodstream. The pancreas is an organ located near the stomach that contains clusters of cells called islets of Langerhans, which are responsible for producing insulin. The parathyroid gland, option A, regulates calcium levels in the blood. The thymus gland, option C, is involved in the development of the immune system. The ovaries, option D, produce hormones like estrogen and progesterone but not insulin. Therefore, the pancreas is the correct gland responsible for producing insulin.

6. Which of the following is the main function of the liver?

A. To produce bile, which helps digest fats
B. To store energy in the form of glycogen
C. To produce proteins that help to clot blood
D. To detoxify harmful substances in the body

Correct answer: D

Rationale: Rationale: A) The liver does produce bile, which helps in the digestion of fats, but this is not its main function. Bile is stored in the gallbladder and released into the small intestine to aid in the digestion and absorption of fats. B) While the liver does store energy in the form of glycogen, this is not its main function. Glycogen is a form of glucose storage that can be broken down into glucose when the body needs energy. C) The liver does produce proteins that help to clot blood, such as fibrinogen and prothrombin, but this is not its main function. These proteins are essential for the blood clotting process to prevent excessive bleeding. D) The main function of the liver is to detoxify harmful substances in the body. The liver processes and removes toxins, drugs, alcohol, and other harmful substances from the bloodstream, making them less harmful and