In an aquatic ecosystem, which zone is most likely to contain photosynthetic, autotrophic organisms?

• A. Photic zone
• B. Aphotic zone
• C. Benthic zone
• D. Abyssal zone

Answer: (A)

Verified step by step guidance

1. Understand the concept of photosynthesis: Photosynthetic organisms, such as algae and phytoplankton, require sunlight to perform photosynthesis, the process of converting light energy into chemical energy.
2. Define the zones in an aquatic ecosystem: The photic zone is the upper layer of water where sunlight penetrates, allowing photosynthesis to occur. The aphotic zone is deeper and lacks sufficient sunlight for photosynthesis. The benthic zone refers to the bottom of the aquatic ecosystem, and the abyssal zone is the deepest part, both of which typically lack sunlight.
3. Identify the requirements for autotrophic organisms: Autotrophic organisms, like plants and algae, rely on sunlight to produce their own food through photosynthesis. Therefore, they are found in areas with adequate light.
4. Match the characteristics of the zones to the needs of photosynthetic organisms: The photic zone is the only zone with sufficient sunlight penetration to support photosynthetic autotrophs.
5. Conclude that the photic zone is the correct answer because it provides the necessary light conditions for photosynthesis, unlike the other zones which are too deep or lack sunlight.