Choose which characteristics are key features of the genetic code.
a) the code has punctuation.
b) the code is degenerate.
c) the code is overlapping.
d) the code has directionality.
e) three nucleotides encode an amino acid.

Three nucleotides encode an amino acid, The code has no punctuation, The code is degenerate.

Explanation:The genetic code has four main features, they are;

1.)Three nucleotides/bases encode an amino acid, there are 20 different amino acids which are the building blocks for proteins.

2.)The genetic code is non-overlapping, for example a sequence UGGAUCGAU is read UGG AUC GAU rather than UGG GGA GAU etc.

3.)The code has no punctuation, so no base serves as a "comma" between groups of bases, therefore the code is read sequencially three bases at a time.

4.)The code is degenerate, meaning more than one codon encodes for the same amino acid. There are 64 possible triplets yet only 20 amino acids so most amino acids are encoded by 2 or more codons. Triplets that code for the same amino acid are known as synonyms.

Other features of the genetic code include;

(1) Code is a Triplet

(2)The Code is Comma Less

(3) The Code is Unambiguous

(4) The Code is Universal

(5) Co-linearity

(6) Gene-polypeptide Parity.