The correct answer is option D. She should place one flower in a similar container, but not pump carbon dioxide into it. She should also give each plant the same amount of water.
In the experiment, a control should be present to compare the effect of the variable in the experiment. In the control sample, all the parameters except the variable should be same as the experimental group. In this way, the comparison of the effect of variable can be easily done in an experiment.
In this case, the variable is amount of carbon dioxide the plant receives. So, Stella should include a control group by placing the plant in the same container and leave it on atmospheric carbon dioxide supply, no extra carbon dioxide should be pumped into it. Also, the amount of water she give to each plant should be the same to maintain the water level as constant.
False. Respiration is providing oxygen for the cells and getting rid of the carbon dioxide, while digestion is transforming food into usable energy.
D. 2H₂O ⇄ H₃O⁺ + OH⁻
H₂O⁺ is known as the hydronium cation and OH⁻ is known as the hydroxide anion.
