Evolution of new diseases I think is the answer you're looking for.
The answer is ( In the early stages the embryos of four different species will look the same .For example, fish embryos and human embryos both have gill slits. In fish they develop into gills, but in humans they disappear before birth. That what makes them different.)
The central nervous system CNS is responsible for integrating sensory information and responding accordingly. It consists of two main components: The spinal cord serves as a conduit for signals between the brain and the rest of the body
Fruit flies share 75% of the genes that cause diseases with humans, so scientists can learn about human genetics by studying fruit fly genetics.
Answer:
Atom, smallest unit into which matter can be divided without the release of electrically charged particles. It also is the smallest unit of matter that has the characteristic properties of a chemical element. As such, the atom is the basic building block of chemistry.
Atom: has equal number of +ve charge (protons) and -ve charge electrons and hence atom has charge.
Neutrons (having no charge) and protons are present in nucleus. Electrons keep revolving around the nucleus in different shells.
