AP BIOLOGY

Detailed explanation-1: -The independent variable should be the amount of water, because the height of the plant is not going to affect the amount of water. The dependent variable would be the height of the plant because it is relying on how much water is being added to it.

Detailed explanation-2: -In the plant experiment, the independent variable could be fertilizer-some plants will get fertilizer, others will not. The scientists change the amount of the independent variable (the fertilizer) to observe the effects on the dependent variable (plant growth).

Detailed explanation-3: -If a plant’s soil has too much water, the roots can rot, and the plant can’t get enough oxygen from the soil. If there is not enough water for a plant, the nutrients it needs cannot travel through the plant. A plant cannot grow if it doesn’t have healthy roots, so the proper balance of water is key when growing plants.

Detailed explanation-4: -In this example, the amount of water given to the plant is controlled by the researcher and, thus, is the independent variable. The growth rate is the dependent variable because it is directly dependent on the amount of water that the plant receives and it’s the variable we’re interested in measuring.

Detailed explanation-5: -Water and light are considered independent because they can be changed, while gravity cannot be changed and is therefore not an independent variable.