Question

Q. With reference to the conditions required for the formation of Coral Reefs, which of the following are incorrect?

Select the correct answer using the code given below:

• A. 1 and 2 only
• B. 2 and 3 only
• C. 1 and 3 only
• D. 1, 2 and 3

Answer 1

The correct option is C 1 and 3 only

Explanation:

Statement 1 is incorrect: Warm water temperature: Corals generally live in water temperatures of 20–32° C.

Statement 2 is correct: Sunlight: Corals need to grow in shallow water where sunlight can reach them. Zooxanthellae (algae) needs sunlight for photosynthesis. Corals have a symbiotic relationship with zooxanthellae; they are dependent on algae for food. Hence, corals rarely develop in water deeper than 50 metres.

Statement 3 is incorrect:

• Corals need calm water: Areas where rivers meet oceans are highly unstable due to the continuous movement of water. Corals need saltwater to survive and require a certain balance in the ratio of salt to the water. This is why corals don't live in areas where rivers drain fresh water into the ocean.
• Saltwater not freshwater: Saltwater is essential for corals. Salts extracted from seawater are necessary for the formation of calcareous shells. This is why corals don’t live in areas where rivers drain freshwater into the ocean i.e. the estuaries.