What are the major elements of life

Robert wants to know which fertilizer will work the best for his grass. what can he do to explore this inquiry?

The circles, or orbits, for electrons are called energy levels. each level can hold only a certain number of electrons. add electrons to each level until you can't add any more. how many electrons can each level hold?

The idea of spontaneous generation was disproved by in a experiment involving jars of meat