Answer:
Both fish and bird embryos exhibit gill slits and a tail.
Explanation:
According to embryology, all vertebrates exhibit similar traits and structures at their embryonic stage. It becomes very difficult to differentiate between the embryos of a fish, and that of a bird, or embryo of a fish, and a human. These traits, however, disappear, as the case may be, as the embryo develops into an adult. For example, in the case of the embryo of a fish, and a bird, both shows gills slits at their respective embryonic stage. However, the gill slits in fish develop into gills, whereas in the case of birds, it disappears as the embryo develops into an adult.
When a meteoroid passes through earth's atmosphere, it heats up due to air resistance. The heat causes gases around the meteoroid to glow. most meteoroids that enter earths atmosphere disintegrate before they hit the ground.
<span>Without variation, there is no difference between members of a population to be "selected for" in the first place. This is a basic tenet of natural selection. A new trait must arise in order to advance or decrease the fitness of the individual, and hence, its ability to pass on its genes.</span>
