Answer:
There are several actions that not only humans have done to cause mass extinction. There are things such as poaching which is simply killing large and rare animals for horns, fur, meat, tusks, etc. These parts can be sold for money or resources. When one type of animal has characteristics of parts that give the poacher lots of wealth, herds or single animals can be tracked down and killed. The number of these animals dwindle down, and if nothing is done to help the animal, it goes extinct.
But things such as nature itself that can cause extinction where humans can do nothing about. For instance, a frog species called "Splendid Poison Frog " has gone extinct for a certain type of fungus that wiped the entire species out, where we can't do anything about.
There are many results on mass extinction, but these two are some that are caused.
Hope this helped.
