Question

A carbohydrate is an organic molecule that contains carbon, hydrogen and, oxygen in a ratio near 1:2:1

Answer 1

A carbohydrate has only Carbon, Hydrogen and Oxygen, with the hydrogen and oxygen in the ratio 2:1.

Examples are glucose  

C 6H12O6 and table sugar  

C12H22O11

A protein is made of amino acids. Amino acids have an amino group which is  

− N H2

.  

So without nitrogen atoms the compound can not be a protein.