Which theory suggests all living things are made up of a cell or cells?

The theory that suggests that all living things are made of cell or cells is called cell theory. In this theory, it describes the properties of cells. According to this theory, the cells are the basic unit of structure of all organisms.

answer: land bridge theory. land bridge theory held that shifting portions of dry land explained the finding of identical species on different continents. plate tectonic theory eventually eliminated the land bridge theory.