Rajesh designed an experiment to test the effect of fertilizer on plant growth. the table on the right shows the data he collected. which changes should rajesh make to his experiment to improve the validity of the data? check all that apply. add twice as much fertilizer to the plants. measure the growth of a plant that did not receive fertilizer. perform additional trials. remove plant 2.

Option B and C

Explanation:

Here in this case Rajesh is concerned about measuring the impact of fertilizers on the growth of plant.  

Thus, a fertilizer is an independent variable and plants are the subject of the experiment.  

In order to improve data validity, Rajesh can conduct the same experiment under the similar conditions for few more times. This will certainly boost his confidence in the result obtained.  

He can also do a comparative study to analyze the experiment result. For doing so he is required to measure the growth of plants that didn't received fertilizer and compare it with the growth of plant that received fertilizers

Hence, option B and C are correct

not sure if this is what you'r looking for nnew= nold