There are possible codons using 4 letters with 3 letters per codon in any order. However, there are only 20 amino acids, and each codon "codes" for one amino acid. What does this mean?

The ancestors of plants that lived in water had plenty of water for the young. angiosperms are a group of land plants that evolved a reproductive trait for living on land. this trait protect young plants by allowing them to grow only when water is present and the conditions for healthy development are right. what trait most likely young angiosperms in this way?