what are all organism made up mostly
Cells are the building blocks of life. All living organisms are made up of cells. The cells were discovered by Robert Hooke in 1665. In the human body there are about 100 trillion to 1014 cells. hey are made up of a single cell. O rganisms like the amoeba, P aramecium are single-celled organisms, they are the oldest forms of life, they existed about 3.8 million years ago. Bacteria, a rchaea, protozoa, unicellular algae and un i cellular fungi are the main groups of unicellular organisms.