How are humans disrupting the nitrogen cycle?

a: sewage runoff

b: excess fertilizer

c: the use of fossil fuels

d: all of the above

Which describes fat? a: a carbohydrate that produces energy b: a nucleic acid that directs cell function c: a lipid that stores energy d: a protein that speeds up a chemical reaction

What is the subscript for oxygen in its molecular formula

The atoms of a solid aluminum can are close together, vibrating in a rigid structure. if the can is warmed up on a hot plate, what happens to the atoms?