The student's scrambled words were unscrambled to reveal geographic terms: island, valley, coastal plain, humus, canyon, butte, delta, and peninsula.
Let's take a look at each scrambled word and find the solution:
nailsd - unscrambles to island.
yellva - unscrambles to valley.
toscala aplin (assuming it's one phrase) - unscrambles to coastal plain.
musthis - unscrambles to humust.
yonnca - unscrambles to canyon.
tetub - unscrambles to butte.
taled - unscrambles to delta.
uslapnine - unscrambles to peninsula.
It looks like these words may be related to a geography lesson, as they all refer to different types of landforms.