Which of the following acid is also a vitamin?

Hari had a problem with carbohydrate, protein and fat metabolism in his body:

a) Name the element he must include in his diet to overcome this problem.

b) Give one symptom of the deficiency disease caused in the above.

The enzyme that is responsible for break down of starch into simple sugar in human mouth is-

Stored energy in an object of weight 10 kg at 6m height from earth surface ($g = 9.8 m{s}^{–2}$):