Final answer:
A eukaryotic protein that is 300 amino acids long would be coded by a DNA template strand with a maximum of 900 nucleotides, due to the triplet codon requirement for each amino acid.
Step-by-step explanation:
The maximum number of nucleotides in the DNA template strand that codes for a eukaryotic protein that is 300 amino acids long could be 900 nucleotides. This is because each amino acid in a protein is coded by a triplet of nucleotides called a codon. Since there are 300 amino acids, you need 300 triplets, which equals 900 nucleotides (300 amino acids × 3 nucleotides/amino acid = 900 nucleotides).