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.
it dates back to the Precambrian era
First of all, it makes algae grow, because pesticides and stuff provide too many nutrients. Algae needs a lot of oxygen and so the fish begin to die off because the algae is taking all the oxygen out of the lake. Next, it causes biodiversity to drop, meaning that species are beginning to get less varied. Water pollution harms the lakes and is a concern because the effects of it on species and the water will stay.
The flight or fight hormone, adrenaline
You can tell by similar genetic features, eye colour, hair type and colour
