Completar frases Cell Theory ObjectivesVersión en línea Cells theory objectives por Michelle Testa 1 microscope unicellular multicellular functions organisms functions react cell cells structures new nutrients cells microscopic knobs living cells structures grow wastes light microscopes detail processes Lenses slide eyepiece old Low High All things and reproduce ; they take in , water , food and get rid of ; they to their environment ; and all living things are made of . Living things , also called , that are made of only one cell are organisms . Living things that are made of many cells working together are organisms . Cells make up the of organisms . This means that they make up the body parts of living things . Cells do the of organisms . This means that they do the that keep an organism alive like exchanging oxygen and carbon dioxide , taking in food , and making energy . Cells are , meaning that they are too small to see with the human eye . Scientists need to see cells . The invention of the helped scientists discover that all living things are made out of . The of a microscope is where you look through . The holds the specimen on the stage , and a shines up and through . You can adjust the focus with the focusing . make the cells appear larger . power lenses make the specimen under the microscope a little bit bigger , and without a lot of detail . power lenses make the specimen much bigger and show much more . The theory has three parts : 1 - all living things are made of . 2 - cells make up the and of living things . 3 - cells must come from ( pre - existing ) cells .