Hello.
1. An organism that has only dominant genes or only recessive genes is considered homozygous. A red plant that is RR is homozygous. An organism that has bothdominant and recessive genes is considered heterozygous. A red plant that is Rr is heterozygous.
2. Heterozygous means that an organism has two different alleles of a gene. For example, pea plants can have red flowers and either be homozygous dominant (red-red), or heterozygous (red-white). If they have white flowers, then they are homozygousrecessive (white-white). Carriers are always heterozygous.
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