Question

in many areas on earth, the carbon cycle is being influenced by an increase in the amount of fossil fuels being burned by humans. when fossil fuels are combusted, carbon dioxide is released into the atmosphere. which of the following describes a possible effect that an increase in carbon dioxide in the atmosphere would have on an ecosystem? plant productivity would increase because more carbon dioxide would be available for photosynthesis. animal productivity would increase because more carbon dioxide would be available for cellular respiration. plant productivity would completely stop because plants cannot use carbon dioxide for life processes. all of the organisms would immediately die because carbon dioxide is poisonous to both plants and animals.

Explanation:

To solve this, we analyze each option:

• Option 1: Plants use \( \text{CO}_2 \) for photosynthesis (to make glucose). More \( \text{CO}_2 \) would provide more raw material for photosynthesis, potentially increasing plant productivity.
• Option 2: Animals use \( \text{O}_2 \) for cellular respiration, not \( \text{CO}_2 \). So this is incorrect.
• Option 3: Plants use \( \text{O}_2 \) (not \( \text{CO}_2 \)) for cellular respiration. Thus, this is wrong.
• Option 4: Plants need \( \text{CO}_2 \) for photosynthesis, so they wouldn’t stop. Incorrect.
• Option 5: \( \text{CO}_2 \) is not poisonous to plants (they use it for photosynthesis) or animals in normal amounts. Incorrect.

Answer:

A. Plant productivity would increase because more carbon dioxide would be available for photosynthesis.