Food is the most vital product of the agriculture sector. But there other non-food products critical to the economy generated in this multi-billion dollar industry, including cotton, wool and tobacco. Prior to the Great Depression, government subsidies to the agriculture sector were relatively limited.
Cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that cells are the fundamental unit of structure and function in all living organisms, that all cells come from preexisting cells, and that all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.
All cells have a membrane. Cell membranes are the outer layers that hold the cell together. They let nutrients pass into the cell and waste products pass out. Not everything can pass through a cell membrane. What gets through and what doesnât depends on both the size of the particle trying to get in and the size of the opening in the membrane. Cells also have a nucleus. This is the cellâs control center. Cells continually divide to make more cells for growth and repair in your body. The nucleus contains the information that allows cells to reproduce, or make more cells. Another important part of a cell is the mitochondrion. This is the part of the cell where food and oxygen combine to make energy. You know that you need air to breathe. It is the oxygen in air that your body really needs.