What do you call several overlapping and interconnected food chains?
trophic levels
a food web
ecology
none of the above

The air that we breath is made mostly of which gaseous molecule

Two objects of different mass start from rest, are pulled by the same magnitude net force, and are moved through the same distance. the work done on object 1 is 900 j. after the force has pulled each object, object 1 moves twice as fast as object 2. how much work is done on object 2?

Observations show that interstellar clouds can have almost any shape and