Similarity of structures due to common ancestry is called

Similarity of structures due to common ancestry is called homology.

Explanation:

Homology is the relationship that exists between two different organic parts when their genetic determinants have the same evolutionary origin or a common ancestry, that is, it is a feature or characteristic that is shared by all descendants of a common ancestor, and not shared with other groups. For example, the arrangement and structure of limbs in vertebrates are similar, these similarities then come from a common ancestor to all vertebrates.

answer:

convection currents in the magma drive plate tectonics. heat generated from the radioactive decay of elements deep in the interior of the earth creates magma (molten rock) in the aesthenosphere. the aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the earth that extends to 2900 km.