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. . Edema, characterized by swelling due to fluid buildup, can be a sign of:

A. Heart failure
B. Liver disease
C. Lymphatic system dysfunction
D. All of the above

Correct answer: D

Rationale: Edema, which is the accumulation of fluid in tissues leading to swelling, can be caused by various medical conditions. Heart failure can result in fluid retention due to the heart's inability to pump effectively, leading to edema. Liver disease can cause edema by impairing the liver's ability to produce proteins that help maintain fluid balance. Dysfunction of the lymphatic system can also lead to edema, as the lymphatic vessels play a crucial role in draining excess fluid from tissues. Therefore, all the options (heart failure, liver disease, and lymphatic system dysfunction) can contribute to the development of edema, making 'All of the above' the correct answer.

3. Which of the following is NOT a state of matter?

A. Solid
B. Liquid
C. Gas
D. Superfluid

Correct answer: D

Rationale: While superfluids exhibit some liquid-like properties, they are a distinct state of matter with unique characteristics beyond the traditional solid, liquid, gas, and plasma classifications.

4. Which condition involves an overactive immune system attacking healthy tissues, leading to inflammation and damage?

A. Immunodeficiency
B. Autoimmune disease
C. Allergy
D. Cancer

Correct answer: B

Rationale: The correct answer is B: Autoimmune disease. Autoimmune diseases occur when the immune system mistakenly attacks healthy cells and tissues in the body, leading to inflammation and damage. Immunodeficiency (option A) is the opposite, where the immune system is weakened or not functioning properly. Allergies (option C) involve the immune system overreacting to harmless substances. Cancer (option D) is characterized by uncontrolled cell growth, not by the immune system attacking healthy tissues.

5. Which element has the highest melting point of any element?

A. Tungsten
B. Iron
C. Platinum
D. Carbon

Correct answer: D

Rationale: Diamond's strong covalent bonds between carbon atoms make it incredibly resistant to heat and pressure, giving it the highest melting point.