Autoimmune diseases occur when the immune system mistakenly attacks healthy body tissues. What is a potential cause of autoimmune diseases?

Correct Answer: C

Rationale: Autoimmune diseases result from a breakdown in immune cell self-tolerance mechanisms, leading to the immune system mistakenly attacking healthy body tissues. While deficiencies in essential vitamins and minerals or exposure to environmental toxins can impact overall health, they are not direct causes of autoimmune diseases. Deficiency in essential vitamins and minerals may weaken the immune system, making it more susceptible to various health issues but does not directly cause autoimmune diseases. Exposure to environmental toxins can trigger immune responses, but autoimmune diseases specifically stem from the breakdown of self-tolerance mechanisms within immune cells. Therefore, the correct answer is a breakdown in immune cell self-tolerance mechanisms.

Correct Answer: B

Rationale: A zoonotic disease is a disease that can be transmitted from animals to humans. Influenza is an example of a zoonotic disease as it can be transmitted from animals such as birds and pigs to humans. The common cold (option A) is caused by human rhinoviruses and is not considered a zoonotic disease. Malaria (option C) is transmitted through the bite of infected mosquitoes and is not considered a zoonotic disease. HIV/AIDS (option D) is caused by the human immunodeficiency virus and is not considered a zoonotic disease.

Correct Answer: A

Rationale: A population is defined as a group of organisms of the same species living in the same area and interacting with one another. Option A correctly describes this definition by specifying that the organisms are of the same species and share a common geographical location. Options B, C, and D are incorrect because they do not accurately define a population in biological terms. In this context, a population specifically refers to a group of organisms belonging to the same species, not higher taxonomic ranks like genus, kingdom, or phylum.

Correct Answer: A

Rationale: A food chain is a linear sequence of organisms where each organism consumes the one below it and is consumed by the one above it. This transfer of energy through feeding relationships is a fundamental concept in ecology to understand how energy flows through an ecosystem. In a food chain, energy is transferred from producers (plants) to primary consumers (herbivores), then to secondary consumers (carnivores), and so on. Each step in the food chain represents a trophic level, and energy is lost as heat at each level, resulting in a pyramid-shaped energy flow. Food webs, on the other hand, represent a more complex network of interconnected food chains within an ecosystem. Habitats refer to the specific environments where organisms live, and biomes are large geographical areas characterized by specific climates and vegetation types. Therefore, the correct answer is 'Food Chain' as it specifically describes the linear transfer of energy through feeding relationships in an ecosystem.

Correct Answer: C

Rationale: The correct answer is Acetic acid (CH3COOH) because it is a weak acid that only partially dissociates in water, resulting in a lower concentration of H+ ions compared to strong acids like hydrochloric acid (HCl), sulfuric acid (H2SO4), and nitric acid (HNO3) which completely dissociate in water. Weak acids do not fully ionize in water, leading to a lower concentration of H+ ions in solution. Hydrochloric acid, sulfuric acid, and nitric acid are strong acids that completely dissociate in water, producing a higher concentration of H+ ions. Therefore, they are not examples of weak acids.