The answer is d but can anyone explain why and if not don't answer

What is the percentage composition of carbon in the compound ch4

The number to the right of an element's symbol (ex. c-12) identifies the of an isotope.

Which of the following contributes to the structural rigidity of cellulose? adjacent glucose polymers are stabilized by hydrogen bonding. glucose residues are joined by (α1→4) linkages. cellulose is a highly branched molecule. the conformation of the glucose polymer is a coiled structure.