1) India is known as a subcontinent because it has distinct geographical features which is not shared by other Asian countries, and has a unique system of governance as well. The Indian subcontinent fits the criteria for a subcontinent, which includes geographical features or governmental system which is different from those of surrounding nations. The Indian subcontinent resides in south-central Asia, and forms the shape of a large peninsula.
2) Arabian Sea, Bay of Bengal and Indian Ocean.
3) i) In the mainland it is 6,100 km.
ii) 7,517 km in the entire geographical coast of the mainland plus the island groups Andaman & Nicobar located in the Bay of Bengal and the Lakshadweep in the Arabian Sea.
4) Opening of Suez Canal was important to India's trade as India's distance from Europe has been reduced by 7000 km.
5) The Prime Meridian is an imaginary line that is similar to the Equator which divides the earth into eastern and western hemispheres. It is sometimes also referred to as the Greenwich Meridian.
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