Question: 4. what is the difference between an organism that is homozygous or heterozygous for an allele?
Answer: Homozygous means that the organism has two copies of the same allele for a gene. ... 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).