A group of scientists believes that a pigment found in red vegetables helps cells to live longer. They test their theory by injecting this pigment into live cells growing in a test tube. After two days, the scientists count the number of healthy cells in the test tube and compare the results to a tube of cells that did not receive an injection of this pigment. What is the limitation of this experiment?

littering streams           is the answer

i believe the answer would be b. hope it : )

answer:

convection currents in the magma drive plate tectonics. heat generated from the radioactive decay of elements deep in the interior of the earth creates magma (molten rock) in the aesthenosphere. the aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the earth that extends to 2900 km.