Which of the following is a fossil fuel?

$(a)$ Mention any two advantages of constructing dams.
$(b)$ Name a dam which was a subject of much opposition from locals as well as $NGOs$.
$(c)$ Mention any three problems which may arise due to the construction of large dams.

In which regions are the severe effects of deforestation observed?

List two main causes of the pollution of water of the river Ganga. State how pollution and contamination of river water prove harmful for the health of the people of neighbouring areas.

The greenhouse effect is caused by an increase in the concentration of which gas in the atmosphere?

Give one protective function of forest.