Plz help with questions giving brainlist

A unicellular organism has only one cell, such as bacteria, protists, and yeast. A multicellular organisms is consisted of 2 or more cells, such as tissue organs, and humans.
Modern cell theory is the theory that cells are the basic structural and organizational of both single and multi cell organisms. This is when cells divide, pass on hereditary info., and contain energy that flows through them.
Sorry I don’t understand the third question.
Humans are multicellular organisms, heterotrophic, and reproduce through sexual relations. Hope this helped :)

1.unicellular consist of a single cell while multicellular consists of multiple cells

2.The modern version of the Cell Theory includes all known living things are made up of one or more cells, all living cells arise from pre-existing cells by division, all cells are basically the same in chemical composition in organisms of similar species.