The main constituent of bio-gas is _________ .

In west Asian countries, electricity is produced using petroleum products. These fuels are called ______________.

Biogas can be prepared from __________.

A tidal power station in the world was established in the year ____________

Pollution is comparatively less in _______.

____________ is used as fuel in Kayamkulam thermal powerstation

Where is the windfarm located in Kerala?

Name the wrong one from the following