Which of the following ecological factors will result in food shortage?

Step 1: Analyze the question We need the ecological factor that leads to a shortage of food. Think about what directly affects food production (plants, crops, and the animals that feed on them).

Step 2: Explain the concept Food in an ecosystem begins with producers (green plants), which depend on climatic and soil factors such as water, light, and temperature. If any of these fails, producers decline, and the consumers that depend on them also suffer.

Step 3: Evaluate each option

• A. Drought: A prolonged period without adequate rainfall. Plants wilt and die, crop yields fall, and pasture dries up. Food becomes scarce for humans and animals alike. This directly causes food shortage.
• B. Low rate of reproduction: This reduces population size, so it would lessen competition for food, not cause a shortage.
• C. Emigration: Individuals leaving an area lowers the population and reduces pressure on food. It does not cause shortage.
• D. Topography: This is the physical features of the land (hills, valleys, slopes). It influences the distribution of organisms, but it is not a direct cause of food shortage.

Step 4: Answer The correct option is A. Drought, because it directly reduces the growth of plants, the base of all food chains.

Tip: In ecology questions, ask yourself whether a factor reduces food supply (such as drought, flooding, pests, or soil infertility) or reduces the number of consumers (such as emigration, low birth rate, or predation). Only the first type causes food shortage.