Please help me!
You observe that grass seems to grow better in soil than it does in gravel. Design a scientific experiment to test this. What is the independent variable? What is the dependent?

Answer and explanation:

To address this question, we could design an experiment where the effect of soil and gravel can be tested independently. One approach is to test this via Completely Random Design (CRD). Here, the treatments would be assigned to experimental units completely at random and each treatment will be tested in replication (e.g. triplicates).

The treatment levels would be (1) Grass growing in the soil (triplicates) and (2) grass growing in the gravel (triplicates). There will be total 6 experimental units and they will be placed randomly. The growth parameters of grass would be then tested after growing for a certain period of time, let's say 90 days.

After this period, the grass will be harvested and the biomass, root length and shoot length will be measured. Because each treatment has three replicate, we will have a clear estimation of soil and gravel on plant growth. The standard deviation would help estimate the effect of natural variations in different treatments. However, they would be consistent because of same environment given for the growth.

The independent variables would be "soil and gravel" and dependent variables would be "growth parameters of the grass (plant root and shoot length and biomass)".

affects the water bodies: excessive use of fertilizers causes eutrophication. the fertilizers which are used on plants affect the quality of land on which it is used, further causing erosion of soil. the fertilizers used on plants contain harmful chemical fumes which affect the environment.