Question

5.Plants of the same species and the same initial height were exposed to a constant number of hours of light each day. The number of hours per day was different for each plant,but all other environmental factors (soil type, amount of water given, etc.) were the same. At the conclusion of the investigation, the final height of each plant was measured. The following data were recorded: 2 hours, 5 cm; 4 hours, 12 cm; 6 hours, 18 cm; 8 hours, 25 cm; 10 hours, 34 cm; 12 hours, 35 cm; 14 hours, 35 cm.

Select independent variable:
a) Number of hours per day
b) Final height of each plant
c) Soil type
d) Amount of water given

Answer 1

The independent variable in the experiment is the number of hours of light exposure per day, while the dependent variable is the final height of each plant. Controlled factors include soil type, water amount, and plant food to ensure valid results.

Step-by-step explanation:

The independent variable in the experiment described is the number of hours per day that the plants were exposed to light, which varied for each plant. However, the investigation assessed the effect of different light durations on the final height of each plant, making the final height of each plant the dependent variable. In any controlled experiment, it is crucial to manipulate only one variable (independent variable) to observe the outcome's impact (dependent variable) while keeping other factors constant so that any differences in the outcome can be attributed to the changes in the independent variable alone.

In the context of plant growth experiments, the controlled factors would likely include the soil type, amount of water given, and potentially the type of soil and amount of plant food. These factors can affect plant growth and must be kept consistent across test subjects to ensure that the data collected reflects the effects of the independent variable.