Answer the following question given this paragraph: The cell is the site of all of the basic biochemical processes that keep organisms alive. To do its work, the cell needs substances such as oxygen, water, and glucose. The cell also must get rid of substances, including wastes such as carbon dioxide. In addition, harmful substances must be kept out of the cell. Controlling what enters or leaves a cell is an important role of the cell membrane. Q: What structure is the site of all of the basic biochemical processes that keep organisms alive? A:

1). particle;
2). Atom;
3). Element;
4). cell;
The answer is:
4).