Which of the following is NOT a type of antibody?

Correct Answer: C

Rationale: A) IgA: This is a type of antibody found in mucosal areas such as the gut, respiratory tract, and genitourinary tract. It plays a role in mucosal immunity. B) IgM: This is a type of antibody produced during the primary immune response and is the first antibody to be produced in response to an infection. C) Interferon: Interferons are signaling proteins produced by cells in response to viral infections. They play a role in the immune response by interfering with viral replication, but they are not antibodies. D) IgG: This is the most abundant type of antibody in the bloodstream and is involved in long-term immunity. Therefore, the correct answer is C) Interferon, as it is not a type of antibody.

Correct Answer: C

Rationale: Endospores are the correct answer. Endospores are dark, round structures observed within some bacterial cells. They are highly resistant dormant structures formed by certain bacteria in response to harsh environmental conditions. Ribosomes are not dark, round structures within bacterial cells; they are responsible for protein synthesis. Flagella are long, whip-like appendages used for movement and are not dark, round structures within bacterial cells. Capsules are outer layers of polysaccharides that some bacteria produce for protection and adherence, not dark, round structures within bacterial cells.

Correct Answer: B

Rationale: A) Community refers to all the populations of different species living and interacting in a particular area. Since the question specifies organisms of the same species, community is not the correct answer. B) Population is a group of organisms of the same species living in a particular area. This term specifically refers to individuals of the same species and their interactions within a defined area. C) Ecosystem includes all the living organisms (biotic factors) and non-living components (abiotic factors) in a particular area and their interactions. While populations are part of an ecosystem, the term 'ecosystem' is broader and includes multiple populations. D) Habitat refers to the specific environment where an organism lives, including the physical and biological factors. It is the place where a population or individual organism resides, but it does not specifically refer to a group of organisms of the same species.

Correct Answer: B

Rationale: The correct answer is B: Neutralization. When an acid and a base react, they neutralize each other's properties, resulting in the formation of water and a salt. Choice A, 'Precipitation,' refers to the formation of a solid from a solution during a chemical reaction. Choice C, 'Oxidation-reduction,' involves the transfer of electrons between reactants. Choice D, 'Photolysis,' is a reaction where a compound is broken down into smaller components by light energy. Therefore, the most appropriate term for a reaction between an acid and a base is neutralization.

Correct Answer: B

Rationale: Chest pain or discomfort is the most common symptom of angina pectoris. This pain is often described as squeezing, pressure, heaviness, tightness, or pain in the chest. Fever and chills, sudden onset of severe shortness of breath, and numbness or tingling in the extremities are not typical symptoms of angina pectoris. The pain associated with angina is usually triggered by physical or emotional stress and typically subsides with rest or medication, distinguishing it from other conditions.