An object in which no light rays can pass through is called?

When did the Government of India Himplemented the Wildlife Protection Act? 

The method of irrigation by traditional methods is –

Which is correctly matched? 

In which year 'Bengal Sati Regulation' was banned for the first time to prevent the practice of Sati? went ?

Which of the following is the correct descending order of volume percentage of gases in atmospheric composition?

Chipko Movement' is related to?

Geography is a science to study the earth as its center' who said like this?