Freaking out on the interstate, meet me in the hallway, driver’s license , flashing lights
Answer:
The most closely related are amphibians and reptiles.
The least related are amphibians and mammals
Explanation:
Amphibians broke off from reptiles, birds, and mammals around 260 millions years ago and next up are the reptiles which broke off around 225 million years ago. So they are the most closely related
Mammals are the last to break off, around 200 million years ago. So they are the least related to amphibians.
The region that would be eroded the most would be those at the slopes of the mountain. When heavy rainfall comes, the soil in these regions gets soften thus being forced down forming a run-off due to the force of gravity. These eroded soil would eventually continue to the valleys thus causing landslides.
B. I think I'm not so sure but that's my best guess.