According to the passage, how many genetic species of horses are known today

* Hướng dẫn giải

Đáp án là A.

Đ1: Although fossil remains of “dawn horses” have been excavated in several sites in Wyoming and New Mexico, these animal, which were biologically different from contemporary horses, had been extinct several millennia before onset of the Indian era. -> Có 2 loại là “dawn horses” và “contemporary horses”