How many basecodes
are there for one amino acid

Proteins are built from a basic set of 20 amino acids, but there are only four bases. Simple calculations show that a minimum of three bases is required to encode at least 20 amino acids. Genetic experiments showed that an amino acid is in fact encoded by a group of three bases, or codon. The code is nonoverlapping.

d. sodium chloride ions.

it has one origin of replication, but it proceeds in two directions - d)