Final answer:
Genes send messages within the cell and to other cells in the form of messenger RNA (mRNA) through complementary base pairing.
Step-by-step explanation:
Genes send messages within the cell and to other cells in the form of a messenger RNA (mRNA), which is made possible through complementary base pairing. The DNA sequence is transcribed into mRNA, where the RNA sequence is complementary to the sequence of the DNA. For example, if the DNA strand has a sequence 5'-AATTGCGC-3', the sequence of the complementary RNA is 3'-UUAACGCG-5'. The mRNA interacts with ribosomes and other cellular machinery to synthesize proteins from the coded message, with each codon coding for a single amino acid.