It is the branch of zoology which includes the study of insects, and by the definition of entomology it includes the study of various different earthly animals in other arthropod groups or other phyla, which includes land snail, arachnids, arthropod, earthworms, and slugs. Like several of the different fields which are distributed within zoology, entomology is a taxon based category which focuses of scientific study on insect and their related groups. Hence entomology therefore overlaps with a cross section of topics as diverse as molecular genetics, behaviour, biochemistry, systematic, physiology, developmental biology, ecology, morphology. The branches of Entomology include Insect Ecology, Insect Morphology, Insect Pathology, Insect Physiology, Insect Taxonomy, Insect Toxicology, and Industrial Entomology. It also includes Medical Entomology, Economic Entomology. The Medical Entomology is a branch focused on the insects and arthropods which impact human health.