Which of the following is NOT a freshwater aquatic ecosystem?

• A. Coral reef
• B. Pond
• C. River
• D. Freshwater marsh

Answer: (A)

Verified step by step guidance

1. Step 1: Understand what defines a freshwater aquatic ecosystem. Freshwater ecosystems are bodies of water with low salt concentration, typically less than 1%. Examples include ponds, rivers, lakes, and freshwater marshes.
2. Step 2: Review each option and classify it based on its water type. Ponds, rivers, and freshwater marshes all contain freshwater and fit the definition of freshwater ecosystems.
3. Step 3: Examine the coral reef option. Coral reefs are marine ecosystems found in saltwater environments, typically in shallow, warm ocean waters.
4. Step 4: Compare the salt concentration and habitat type of coral reefs with freshwater ecosystems. Since coral reefs are saltwater habitats, they do not belong to freshwater aquatic ecosystems.
5. Step 5: Conclude that the coral reef is NOT a freshwater aquatic ecosystem, while the other options are.