Which of the earth's layers is represented by the number two (2) on the image above?

In the above-given question, there is no image provided.

Considering an image of the earth's various layers (image uploaded below), the numbers are mentioned from the external region to the extreme internal part of the earth.

The layer which is marked as 1 is the crust which is the hard, rigid portion of the earth.

Layer 2 is the mantle which is comprised of silicate rocks and where the convection currents are generated that is responsible for the motion of lithospheric plates.

The layer 3 is the outer core which is liquid in nature and is comprised of hot, molten, denser rocks and other siderophile elements.

Layer 4 is the inner core, which forms the extreme internal layer, comprised of solid rocks that are very dense. The inner core is solid in nature.

Thus, from the image, we can consider that the layer 2 is the Mantle.