In biology, homozygous refers to having identical alleles for a particular trait located at similar loci on paired chromosomes. In diploid organisms, there are two alleles for each trait or gene in each pair of chromosomes in the same location, or locus. One allele is inherited from the father and the other from the mother. An allele is one of two or more alternative forms of a gene, and they are found at the same place on chromosomes. Homozygous individuals have two identical versions of a genomic marker, while heterozygous individuals have two different versions of that marker.

Some key points to note about homozygous in biology are:

• Homozygous organisms can be either homozygous dominant or homozygous recessive.
• Homozygous dominant organisms have two dominant alleles, while homozygous recessive organisms have two recessive alleles.
• Homozygous traits can include eye color, hair color, and genetic conditions.
• Heterozygous individuals have two different alleles for a particular trait.

In summary, homozygous in biology refers to having identical alleles for a particular trait located at similar loci on paired chromosomes. It is an important concept in genetics and can have implications for traits and genetic conditions.