Why does australia have such an unusual variety of spiders?

Spiders are one of the major predators of insects, so there might be a huge increase in insect populations. Spiders are usually around devour trees,crops,and grass
That’s basically there ecosystem
That’s why there are allot of spiders in Australia
Hope this helped!
Let’s hop in the
Future 0.-
(That’s a phrase of mine =P)

What orders do you have in your chart

It is called the medulla oblongata or people usually call it medulla. it is the lower half of the brain stem continuous with the spinal cord.