All insect has three main body parts. The head is the part of the insect that contains the brain and the two compound eyes. The two antennae are attached to the head. The thorax is the body section between the head and the abdomen. This section operates the wings and legs. The legs attach to the thorax.
The collection of all the genes and the various alternate or allelic forms of those genes within a population is called its gene pool. Genetic variation within a population is measured according to the number of different alleles of all genes and the frequency with which they appear. Variation is high when there are many different allelic forms of all genes and when there are many different combinations of those alleles.
These chromosomes are referred to as homologous chromosomes. Diploid organisms have one copy of each gene (and, therefore, one allele) on each chromosome. If both alleles are the same, they and the organism are homozygous with respect to that gene. If the alleles are different, they and the organism are heterozygous with respect to that gene. The word allele is a short form of allelomorph (other form), which was used in the early days of genetics to describe variant forms of a gene detected as different phenotypes.