Primates have the greatest of any mammalian group

Primates have the greatest brain size to body size ratio of any mammalian group.

Explanation:

Primates can be described as mammals which have digits. Apart from having digits, primates comprise of features like skull and teeth. Primates undergo sexual reproduction to produce offsprings and are characterized of being placental mammals.

Primates are organisms that have the largest size of the brain tin relation to their body ratio. Among primates, Humans have the largest brain to body size ratio, making them by far the most intelligent organism in the animal kingdom.

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.