Landforms tend to weather and wear down over time. the grand tetons are an area of steep, rugged mountains that are thought to be about 9 million years old. what change would an observer most likely see if he could look at the mountains again after another 9 million years?

Explanation:

Over time, steep hills are weathered. Weathering and erosion break down and remove rocks and soil such that the mountains tops become more rounded and the rocks and soil deposit on the hillsides, making them less steep.

After another 9 million year of erosion and deposition, an observer could expect the mountains to be less steep and more rounded.

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).   so the answer is a.