You are told that the cells on a microscope slide are plant, animal, or bacterial. you look at them through a microscope and see cell walls and membrane-bound organelles. you conclude correctly that the cells

good one: produce hormones that plants grow.

bad one: the problem with organic matter is that while plant nutrients are needed for crop growth, they can also stimulate excessive growth of the wrong plants – mainly, algae.

yes, because even though a theory has a  lot of evidence to support it, it is not always true