Questions

‘has’ should be replaced with ‘have’.

Amphibians are one of the most sensitive groups to change, whether that is caused by habitat loss, invasive species, disease, trade or climate change. Their sensitivity to environmental threats has been generally linked to the observation that amphibians are characterized by a rather permeable skin. Given their complex life cycles and other traits, amphibians are often recognized as indicators of ecosystem health.

Indus Valley Civilization flourished during 2500-1750 B.C. Indus Valley Civilization is also called as Bronze age civilization.

History of Shimla goes back to the period of Anglo –Gurkha war in the year 1808-09. The British connection with the area developed only after this battle between the Sikh rulers of these hills and the Gurkhas from Nepal.

In 1782 Colebrooke was appointed through his father's influence to a writer-ship with the East a India Company in Calcutta.Lord Wellesley appointed him honorary professor of Hindu law and Sanskrit at the college of Fort William.