What is the layer of the earth where mantle convection occurs and on which the earth's crust rests?

In the passage this question was provided for, you should have been able to locate the fallowing text: "the outer layer of the mantle; made up of plastic or semi-molten rock" and many others to imply this answer.

Asthenosphere

spiders belong to a group of arachnids.

arachnids have the following traits :

they have two body parts.

they have eight legs unlike insects which have 6 legs.

they have no wings.

these traits distinguish them from insects.

the information that antonio is doubting us the statement that spiders differences are as a result of being first to evolve.

this is because the evolution of one species is independent of the other species.