Question

1. three redwood trees are kept at different humidity levels inside a greenhouse for 12 weeks. one tree is left outside in normal conditions. height of the tree is measured once a week.

a. independent variable
_____________________
b. dependent variable
_____________________
c. control group
_____________________
d. experimental group
_____________________

Explanation:

a. Independent Variable

The independent variable is the factor that is manipulated in an experiment. Here, the humidity levels are changed (different levels) to observe its effect on tree height. So the independent variable is the humidity level.

The dependent variable is the factor that is measured and depends on the independent variable. The height of the tree is measured to see how it changes with different humidity levels, so it's the dependent variable.

The control group is the group not exposed to the independent variable manipulation, used for comparison. The tree left outside in normal conditions isn't subjected to the greenhouse humidity changes, so it's the control group.

Answer:

Humidity level

b. Dependent Variable