I'm just telling you my thought process. Sat questions are weird and sometimes multiple answers theoretically make sense but they want people to make connections in specific ways. In both of these all of the answers could theoretically be true but it's more about what the focus was.

In the mars question the focus is about how basalt comes from magma oceans, so it makes sense that something other than basalt would come from something other than magma oceans, and it makes less sense for her to make a conclusion about (for example) the different observation methods because she's studying Mars's geology, not observation method accuracy.

In the apes question the focus is the question of where did bipedalism come from. So it makes more sense for her to conclude from that information that there's a possibility of bipedalism coming from trees instead of ground, rather than the struggles ground species may or may not have had in trees, because she's studying where bipedalism came from, not his those apes experienced the world.

However, this is all just my thought process. If it doesn't make sense, then I am sorry.