Kevin decides to find out which fertilizer is best for tomatoes. he pots up three plants, all with the same soil, giving one no fertilizer, giving the second type a fertilizer, and giving the third type b fertilizer. in this experiment, what is the control, or kevin's standard for comparison?

Cancer cells spread to other parts of the body by entering the bloodstream. which of the following organs could prevent a cancer cell in the bloodstream from spreading, and why? a. the spleen, because it releases lymphocytes into the blood b. the peyer's patches, because they release lymphocytes into the blood c. the lymph nodes, because they release lymph into the blood d. the thymus, because it releases lymph into the blood