The big bang
The species "native horse" did go extinct and that is what scientists are talking about. The "equus ferus'' species is still alive though.
the world ending
something
Probably not, but I don't think anyone has proved that it was.
Scientists believe that changes in the Earth's climate cause extinction of trees;P
It depends on what sea. In most coral reefs scientists think that there are 15,000 species.
Scientists estimate that there are between 8.7 million to 9.9 million species on Earth, although the actual number could be much higher due to many species still being undiscovered and undescribed.
Because they are scientists
Why do scientists think related species have similar body structures and development patterns?
Most scientists probably don't think anything about hieroglyphics. Historians know that they are a form of pictorial writing used by the ancient Egyptians.
We do no know exactly what kind of lizard snakes evolved from, but scientists think it was related to monitor lizards.
I wouldn't know for sure but I think its Ancient Moderns