33. Denise and David are testing how plants respond to fertilizer. They use three plants for the experiment. The first is given a cup of Fast Grow Fertilizer with no water. The second is given a teaspoon
of Sunlight Fertilizer with a cup of water. The third plant is given no fertilizer with a cup of water.
Fast Grow
Fertilizer
SunLight
Fertilizer
Plant A
Plant B
Plant C
Which of the following statements explains why Denise and David will not be able to draw a valid
conclusion based on the results of their experiment?
There are not enough different types of plants.
There is no test variable (independent variable).
Results of the experiment need to be presented in a graph.
O More than one test variable (independent variable) has been changed in the experiment.