Daisy made the graph shown to display the data recorded during an experiment. daisy is studying the effect of soil on the growth of plants. three identical plants having a height of 15 cm were used for the experiment. the first plant was planted in type a soil in 4 hours of sunlight, the second plant was planted in type b soil in 6 hours of sunlight, and the third plant was planted in type c soil in darkness. all other growing conditions of the plants were kept constant.
a bar graph titled plant growth is shown. the y axis, labeled height in centimeters, goes from 0 to 3.50. the x axis, labeled week, goes from 1 to 4. each week has 3 bars, type a soil, type b soil, and type c soil. for weeks 1 to 4, bars for type a soil have heights of 1.25 centimeter, 1.50 cm, 1.75 cm, 2.00 cm, bars for type b soil have heights of 2.00, 2.25, 2.50, and 2.75 centimeters, and bars for type c soil have heights of 0.50, 0.75, 1.00, and 1.75 centimeters.
what is wrong with daisy's experimental design?
a) a single variable was used
b) sunlight was not kept constant
c)more than one type of soil was used
d)other growing conditions were not changed