Questions

A Lobster is one which goes black in water and comes out red.

Geothermal energy is heat energy generated and stored in the Earth. Geothermal energy has been used for thousands of years in some countries for cooking and heating. It is simply power derived from the Earth's internal heat.

A Match stick. 

You tear a match out of a matchbook and scratch the head to light it, then the red tip turns black from the flame.

Tether is a rope, chain, or the like, by which an animal is fastened to a fixed object so as to limit its range of movement.

Cord is rope like to tie. Hence, cord is most similar in meaning to tether.

Ashtadhyayi was written by Panini. He was a Sanskrit grammarian who gave a comprehensive and scientific theory of phonetics, phonology, and morphology. Panini was born in Shalatula, a town near to Attock on the Indus river in present day Pakistan.