The gap between two mountains is called Saddle.
Arid
<span>Lacking moisture, especially having insufficient rainfall to support trees or woody plants</span>
I think Tibet is the most tropical
After reviewing the graph you posted above, there is one radioactive isotope that has a half life that is approximate to the same as the estimated time of the origin of Earth.
The radioactive isotope is called Uranium 238. You can also write this out as U-238 or uranium/u. Any of these are acceptable for the answer.
T<span>he Great Migration (in East Africa, mainly Kenya and Tanzania) is principally herds of wildebeest and zebra following their food and water supply.</span>
