Questions

It is composed of Archaean gneisses and schists

Diamond is the hardest substance available on Earth.

Diamond is the hardest substance available on Earth due to the giant molecular structure of diamond in which each carbon atom is covalently bonded to four other carbon atoms. A covalent bond is very strong and requires a large amount of energy to break itself, and diamond has many covalent bonds.

In the annual World University Rankings released by Times Higher Education, the Indian Institute of Science of India has reached 251-300 band from last year's 201-250 band, while Oxford and Cambridge universities are on the top in the Global 1000 list.

The clotting of blood is a chain reaction initiated by the enzyme thrombokinase produced by the platelets. This causes prothrombin to be converted into thrombin in the presence of Ca++ion.

Thrombin combines with fibrinogen  to produce fibrin threads which entangles the corpuscles to form the clot.