Which two bodies of water does the transition zone meet in the east?

The two bodies of water that meet in the transition zone of East Africa are the Nile River  and the lake Victoria.

Explanation:

The transition zone is formed as a result of the earth’s mantle that is situated in the lower side of the mantle on the ground and the upper mantle, which is about 500km. The transitional zone, therefore, has different types of rocks. The reason for the division of the lower and upper mantle is because of the seismic, which happens when there are discontinuities that occur when there is no rearrangement of grains. When the phase changes the temperatures also vary.