Describe why this is a controlled experiment. A. Only one variable is changed
B. two variables are changed
C. the plants grew tall in the control group
D. the plants grew tall in the experiment

Blood made up of red and white blood cells work together to form

Which of the following is a consequence of urban heat islands? increased precipitation downwind of the city? increased precipitation upwind of the city? decreased winds within the city? increased winds within the city?

Which process of living things produces water that enters the water cycle