The portion of the earth where life is found
a) ecosystem
b) macromolecule
c) biosphere
d) community

Which type of intermolecular attractions holds ammonia molecules together with other ammonia molecules?

Why is it incorrect to balance a chemical equation by changing the subscripts? explain.

If you try to move a piano and are unable to move it, did you perform any work in the scientific sense of the word? yes or no?