Answer :
The student planned to conduct an experiment to determine how a change in the pH of water affects the population growth rate of algae.To ensure that her experimental data are valid, she should use the same species of algae in all trials.
To ensure that her experimental data is valid she should check every pH with a sample of algae. She should also write down all the data collected such as what happens when the pH changes and how much algea has grown at an specific pH. In addition, she should collect data multiple times to ensure that the replication of the experiment will result in the same data being obtained.
