Choose the correct statements about the islands of India.
a. Lakshadweep Islands are composed of coral islands.
b. Andaman and Nicobar islands are composed of coral islands.
c. It is believed that Lakshadweep islands are an elevated portion of submarine mountains.
d. It is believed that Andaman and Nicobar islands are an elevated portion of submarine mountains.

Correct Answer: a and d

Let us analyze each statement regarding the islands of India to understand why this option is correct:

1. Statement a: Lakshadweep Islands are composed of coral islands.
(Correct) The Lakshadweep island group, situated in the Arabian Sea, is composed of small coral islands. They were built up by coral polyps over time and were earlier known as Laccadive, Minicoy, and Amindivi.

2. Statement b: Andaman and Nicobar islands are composed of coral islands.
(Incorrect) The Andaman and Nicobar Islands, situated in the Bay of Bengal, are not coral origin islands. Instead, they are volcanic and tectonic in origin.

3. Statement c: It is believed that Lakshadweep islands are an elevated portion of submarine mountains.
(Incorrect) Since Lakshadweep islands are coral deposits (atolls) on top of the Chagos-Laccadive submarine ridge, they are classified as coral islands rather than elevated submarine mountain peaks themselves.

4. Statement d: It is believed that Andaman and Nicobar islands are an elevated portion of submarine mountains.
(Correct) The Andaman and Nicobar chain of islands are elevated portions of submarine mountains (part of the extension of the Arakan Yoma mountain range of Myanmar).

Thus, statements a and d are true, making a and d the correct option.