Question

root match
match the root to its meaning.
hum
stell
neb
cloud
earth
star

Explanation:

The root "hum" is related to earth (as in "humus" which is related to soil). The root "stell" is related to star (as in "stellar"). The root "neb" is related to cloud (as in "nebula").

Answer:

hum - earth
stell - star
neb - cloud