State the role of silica in the metallurgy of copper.

Define metallurgy.

What is the role of cryolite in the metallurgy of aluminium ?

State the role of sun in the origin of life.

Although thermodynamically feasible, in practice, magnesium metal is not used for the reduction of alumina in the metallurgy of aluminium. Why ?

What is the role of renin?

State the role of pancreatic juice in the digestion of proteins.

What is the role of radula in molluscs?