2.1a Hereditary information is contained in genes. Genes are composed of DNA that
makes up the chromosomes of cells.
2.1b Each gene carries a single unit of information. Asingle inherited trait of an individ-
ual can be determined by one pair or by many pairs of genes. A human cell contains
thousands of different genes.
2.1c Each human cell contains a copy of all the genes needed to produce a human being.
2.1d In asexual reproduction, all the genes come from a single parent. Asexually pro-
duced offspring are genetically identical to the parent.
2.1e In sexual reproduction typically half of the genes come from each parent. Sexually
produced offspring are not identical to either parent.