Which of the following metals is present in vitamin $B_{12}$?

In the given figure,what does $A$ indicate?

Due to which property of water is heat distributed uniformly throughout the body of a living organism?

The term "vitamin" was coined by

Which of the following is $NOT$ included in inorganic compounds?

Given below are two statements:
Statement $I$: Low temperature preserves the enzyme in a temporarily inactive state,whereas high temperature destroys enzymatic activity because proteins are denatured by heat.
Statement $II$: When the inhibitor closely resembles the substrate in its molecular structure and inhibits the activity of the enzyme,it is known as a competitive inhibitor.
In the light of the above statements,choose the correct answer from the options given below: