Final answer:
According to Coppens, the characteristic of the eastern side of the rift valley is a semiarid transition zone between the Sahel and the Mediterranean coast. It experiences dry desert-like conditions and has a savanna-type landscape with few forests and more open grasslands.
Step-by-step explanation:
The characteristic of the eastern side of the rift valley according to Coppens is a semiarid transition zone between the Sahel and the Mediterranean coast. The region experiences dry desert-like conditions due to lower levels of rainfall, leading to a savanna-type landscape with few forests, more open grasslands, and sporadic trees. Some places along the Great Rift Valley exhibit these dry conditions.