This experiment was conducted to determine how the presence of earthworms in soil can affect plant growth. The experiment was done by comparing the germination and growth of tomato, green beans and radish plants in soil samples that contiained earthworms, with those that did not contain any earthworms.
1. For this experiment, the independent variable is whether or not the earthworms were present in the soil. The dependent variable is the height of the plants after 8 days. This is determined by using a ruler to measure the height of the 10 plants in each pot and calculating their average height. The constants (control variables) are the environment the plants are kept in (temperature, humidity, light, etc), the size of the pot, the type of plants (namely, tomato, green beans and radish) and the type of soil. 2. The pots are labeled “tomato”, “green beans”, “radish”, “tomato-worm”, “green .....
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