Without staining them you wouldn't be able to see them
The two main variables in an experiment are the independent and dependent variable.
An independent variable is the variable that is changed or controlled in a scientific experiment to test the effects on the dependent variable.
A dependent variable is the variable being tested and measured in a scientific experiment.
The dependent variable is 'dependent' on the independent variable. As the experimenter changes the independent variable, the effect on the dependent variable is observed and recorded.
For example, a scientist wants to see if the brightness of light has any effect on a moth being attracted to the light. The brightness of the light is controlled by the scientist. This would be the independent variable. How the moth reacts to the different light levels (distance to light source) would be the dependent variable.
When results are plotted in graphs, the convention is to use the independent variable as the x-axis and the dependent variable as the y-axis.
I would select A because cells have to divide into smaller cells depending on where they are.
"Waste" -- in the form of urine and feces -- how the body removes the parts of food we ingest that is not used for nutrition and also is a way to rid the body of toxins. The kidneys filter the blood, removing "waste" products such as excess vitamins or drugs (this is why your urine can have a bright color if you take high doses of vitamin c) and liquid waste is held in the bladder before being released. Food travels through the gut to be digested -- broken down into usable bits and waste. After breaking down in the stomach, the material travels through the small and large intestines. The small intestine is lined with villi -- tiny protrusions that add surface area so nutrients can be absorbed into the bloodstream. In the large intestine and colon, water is pulled from the mass so it becomes more solid. Eventually the solidified waste passed through the rectum and out the anus as feces. The build-up of waste in the body can itself be toxic -- if the kidneys do not function properly to clean the waste out, the buildup can be fatal. When the body goes into emergency mode to eliminate a toxic substance -- such as e. Coli in the case of food poisoning -- the intestines don't both absorbing water and the result is the liquid fecal matter being quickly passed through and ejected as diarrhea.
It is mostly glass and fiber glass
