To prepare for an important midterm, zoe studies 90 minutes each night for five nights. zoe's method exemplifies:

The answer would be: Distributed practice
Distributed practice is a method of learning that involves a repeated session of practice over a period of time. It is more effective than a longer session in short period of time. The spacing effect in this method will make it easier to store learned lesson into long-term memory. 

C. gemstones they are the only non metallic mineral from the list.

Nine months old i think but i’m not that sure