Are roots or plant growth making cracks in concrete chemical or mechanical weathering?

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

If we compare and contrast electromagnetic waves with sound waves, all but one statement is true. that is a) sound waves require a medium to travel while electromagnetic waves do not. b) electromagnetic waves can travel through the vacuum of space while sound waves cannot. c) electromagnetic waves must have a medium in which to travel, but sound waves can travel anywhere. eliminate d) sound waves must bounce off of matter in order to travel while electromagnetic waves do not require matter to be present.

What type of matter is made of only one kind of atom