Question

Which of the following statements about coral polyps are correct? \[ \begin{aligned} A.&\ \text{Corals are found mainly in the tropical oceans and seas.} B.&\ \text{Corals do not live in deeper waters, i.e. not more than 200--250 feet below sea level.} C.&\ \text{There should be clean sediment-free water for their growth.} D.&\ \text{Corals survive through coral bleaching in extreme hot conditions.} \end{aligned} \] Choose the correct answer from the options given below:

• A. A, B and D only
• B. B, C and D only
• C. A, B and C only
• D. A, C and D only

Hint:

Conditions required for coral growth: \[ \boxed{ \begin{aligned} \text{Warm Water} &\rightarrow 20^\circ\text{C} - 30^\circ\text{C}, \text{Depth} &\rightarrow \text{Shallow (}\leq 200\text{--}250\ \text{ft)}, \text{Water} &\rightarrow \text{Clear and Sediment-free}, \text{Bleaching} &\rightarrow \text{Stress, Not Survival}. \end{aligned} } \] Mnemonic: “Corals Need Warm, Clear and Shallow Seas.”

Answer 1

The Correct Option is C

Concept: Coral polyps thrive in warm, shallow, clear and sediment-free tropical waters where sunlight can penetrate easily. Coral bleaching is a stress response caused by high temperatures and often leads to coral death if prolonged; it is not a survival mechanism.

Step 1: Evaluate each statement. \[ \begin{aligned} A.&\ \text{True. Reef-building corals are mainly found in tropical oceans and seas.} B.&\ \text{True. Most reef-building corals occur in shallow waters, generally within about 200--250 feet.} C.&\ \text{True. Clean, sediment-free water is essential for coral growth.} D.&\ \text{False. Coral bleaching weakens corals and may eventually kill them.} \end{aligned} \]

Step 2: Identify the correct combination. \[ \boxed{ A,\ B,\ \text{and}\ C } \] Hence, \[ \boxed{\text{(C)}} \]