I may be wrong but I think it’s the second one. They speed up reactions, and there’s a certain enzyme for a certain reaction.
The function of the cell membrane is to protect the cell from any outer surroundings that could be harmful to it.
I believe the answer is c
Answer: Nucleotides
Explanation: DNA is made up of molecules called nucleotides. Each nucleotide contains a phosphate group, a sugar group and a nitrogen base. The four types of nitrogen bases are adenine (A), thymine (T), guanine (G) and cytosine (C).