Why are there so many differences in the properties of peptides and proteins?
a) several amino acid sequences are possible for proteins and peptides
b) some proteins are enzymes while others are not
c) proteins and peptides include nitrogen
d) amino acids form proteins and peptides

Protiens are very important and they are regarded beneficial 
The protiens and peptides differ in their size protiens are relatively small
There are soi many difference among both because
Several amino acid sequences are possible for proteins and peptides
As there are 20 amino acids and different folding structure
so correct option is A
hope it helps

Where is the rest of the question