Question

experimental design quiz
highlight three (3) constants for this experiment.
pea plant clones are given different amounts of water for a three - week period. first pea plant receives 400 milliliters. second pea plant receives 200 milliliters. third pea plant receives 100 milliliters. fourth pea plant does not receive any extra water, the plant only receives natural ways of receiving water. the height of the pea plants is recorded daily

Explanation:

To identify constants in an experiment, we look for factors that remain unchanged across all experimental groups.

1. Type of plant: All are pea plant clones, so the species/genetic makeup of the plants is constant.
2. Duration of the experiment: All plants are observed for a three - week period, so the time length of the experiment is constant.
3. Method of height recording: The height of the pea plants is recorded daily for all plants, so the frequency and method of height measurement (assuming the same tool and procedure) is constant. Another possible constant could be the environment (if it's the same for all plants, like same soil, same light conditions, same temperature), but from the given info, the three mentioned above are clear.

Answer:

1. The type of plant (pea plant clones).
2. The duration of the experiment (three - week period).
3. The frequency of height recording (daily).