Total number of tripeptides possible by mixing of valine and proline is ___________

Uracil is a base present in RNA with the following structure. % of N in uracil is ___________

Given:

Molar mass N = 14 g mol$$^{-1}$$

O = 16 g mol$$^{-1}$$

C = 12 g mol$$^{-1}$$

H = 1 g mol$$^{-1}$$

In a linear tetrapeptide (Constituted with different amino acids), (number of amino acids) $$-$$ (number of peptide bonds) is ________.