Answer;
Genes
The code for heredity is carried on genes in each organism's DNA.
Explanation;
Genes are portions of the genome that codes for a protein or an RNA, Hereditary information that is contained in nucleotide sequence of DNA. The coded information is copied into RNA (through transcription process) and translated into chains of amino acids which eventually link together to make proteins. The hereditary information is passed from one generation to another.
In frogs, different mating seasons are a barrier to reproduction.
