Which of the following factors are needed for the growth of corals 1. Freshwater 2. Clear shallow salt water 3. Plenty of sunlight for photosynthesis 4. Warm water between 23°C and 25°C Select the correct answer using the code given below.?

Option 2 : 2, 3 and 4 only

The correct asnwer is 2, 3 and 4 only.

• Corals are nothing but calcareous rocks, formed from the skeletons of minute sea animals, called polyps.
• The corals live in colonies fastened to the rocky seafloor.
• The corals occur in different forms and colours, depending upon the nature of salts or constituents they are made of.

Ideal conditions for coral growth

• Corals thrive in tropical waters-between 30°N and 30°S latitudes.
• The ideal depths for coral growth are 45 m to 55 m below sea surface, where there is abundant sunlight available.
• The temperature of the water should be around 20°C.
• Clear salt water is suitable for coral growth, while both fresh water and highly saline water are harmful to polyp growth.
• Adequate supply of oxygen and microscopic marine food, called plankton, is essential for growth and existence.
• As the food supply is more abundant on the seaward side, corals grow more rapidly on the seaward side.
• Hence Option 2 is correct.

Freshwaters are very cold and they don’t have the salt that corals need to survive.