Consider the following statements : 1. Most of the world's coral reefs are in tropical waters. 2. More than one-third of the world's coral reefs are located in the territories of Australia, Indonesia and Philippines. 3. Coral reefs host far more number of animal phyla than those hosted by tropical rainforests. Which of the statements given above is/are correct ?

The correct option is (d). Explanation Coral reefs are diverse underwater ecosystems held together by calcium carbonate structures secreted by corals. They are often referred to as the "rainforests of the sea" due to their high biodiversity, though they occupy less than 0.1% of the world's ocean area. Statement-wise Analysis: - Statement 1 is Correct: Coral reefs require specific environmental conditions to thrive, primarily warm water temperatures between 20°C and 29°C. Consequently, the vast majority of coral reefs are located in tropical and subtropical waters between the Tropics of Cancer and Capricorn. - Statement 2 is Correct: The distribution of coral reefs is highly concentrated. The "Coral Triangle," which includes Indonesia, the Philippines, Papua New Guinea, and surrounding areas, possesses the highest marine biodiversity in the world. When combined with Australia (home to the Great Barrier Reef), these territories account for significantly more than one-third of the world's total coral reef area. - Statement 3 is Correct: While tropical rainforests host a greater number of total species (largely due to the immense diversity of insects), coral reefs exhibit greater phyletic diversity. A phylum represents a major body plan or biological classification rank below Kingdom. Coral reefs host representatives from approximately 32 of the 34 known animal phyla, whereas tropical rainforests host only about 9 animal phyla. Key Takeaway: It is crucial to distinguish between species diversity and phyletic diversity. Tropical rainforests have higher species richness (more individual species), but coral reefs have higher phyletic diversity (more distinct evolutionary lineages/body plans).

IAS 2018 — Environment & Ecology Environment & Ecology

2018mcqmedium

Consider the following statements :

Most of the world's coral reefs are in tropical waters.
More than one-third of the world's coral reefs are located in the territories of Australia, Indonesia and Philippines.
Coral reefs host far more number of animal phyla than those hosted by tropical rainforests.

Which of the statements given above is/are correct ?

Official previous-year question

Verified 2 Aug 2026.

Options

A1 and 2 only
B3 only
C1 and 3 only
D1, 2 and 3

Did you get this right?

Solution

The correct option is (d).

Explanation

Coral reefs are diverse underwater ecosystems held together by calcium carbonate structures secreted by corals. They are often referred to as the "rainforests of the sea" due to their high biodiversity, though they occupy less than 0.1% of the world's ocean area.

Statement-wise Analysis:

Statement 1 is Correct: Coral reefs require specific environmental conditions to thrive, primarily warm water temperatures between 20°C and 29°C. Consequently, the vast majority of coral reefs are located in tropical and subtropical waters between the Tropics of Cancer and Capricorn.
Statement 2 is Correct: The distribution of coral reefs is highly concentrated. The "Coral Triangle," which includes Indonesia, the Philippines, Papua New Guinea, and surrounding areas, possesses the highest marine biodiversity in the world. When combined with Australia (home to the Great Barrier Reef), these territories account for significantly more than one-third of the world's total coral reef area.
Statement 3 is Correct: While tropical rainforests host a greater number of total species (largely due to the immense diversity of insects), coral reefs exhibit greater phyletic diversity. A phylum represents a major body plan or biological classification rank below Kingdom. Coral reefs host representatives from approximately 32 of the 34 known animal phyla, whereas tropical rainforests host only about 9 animal phyla.

Key Takeaway:

It is crucial to distinguish between species diversity and phyletic diversity. Tropical rainforests have higher species richness (more individual species), but coral reefs have higher phyletic diversity (more distinct evolutionary lineages/body plans).

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The correct option is (d).

Explanation

Statement-wise Analysis:

Statement 1 is Correct: Coral reefs require specific environmental conditions to thrive, primarily warm water temperatures between 20°C and 29°C. Consequently, the vast majority of coral reefs are located in tropical and subtropical waters between the Tropics of Cancer and Capricorn.
Statement 2 is Correct: The distribution of coral reefs is highly concentrated. The "Coral Triangle," which includes Indonesia, the Philippines, Papua New Guinea, and surrounding areas, possesses the highest marine biodiversity in the world. When combined with Australia (home to the Great Barrier Reef), these territories account for significantly more than one-third of the world's total coral reef area.
Statement 3 is Correct: While tropical rainforests host a greater number of total species (largely due to the immense diversity of insects), coral reefs exhibit greater phyletic diversity. A phylum represents a major body plan or biological classification rank below Kingdom. Coral reefs host representatives from approximately 32 of the 34 known animal phyla, whereas tropical rainforests host only about 9 animal phyla.

Key Takeaway: