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.
The frequency of different alleles varies throughout the population. Some genes may have two alleles with equal distribution. For other genes, one allele may be common, and another allele may be rare. Sometimes, one allele is a disease-causing variation while the other allele is healthy.