Provide a large surface area for photosynthesis to take place.
1. the independent variable (the thing the person is changing) is the different type of mouthwash. the dependant variable (the affect of the independent variable) is how much bacteria the mouthwash kills
2. the independent variable for this one would be the plants growing in soil or water, and the dependant variable is how do the plants grow.
Plant cells have a cell wall and large central vacoule, and chloroplasts that animal cells do not.
The circulatory system circulates blood around the body. The blood passes through the lungs, where it loses carbon dioxide and gains oxygen. All cells need oxygen to function and carbon dioxide is a form of waste produced in the cells. The digestive system breaks down food and absorbs.
Infectious diseases are caused by microscopic germs (such as bacteria or viruses) that get into the body and cause problems. Some — but not all — infectious diseases spread directly from one person to another. Infectious diseases that spread from person to person are said to be contagious.
