I need help with question 4

Question 4 (Essay Worth 10 points) (08.07 MC) Leo is testing different types of greenhouse material to determine which type is most effective for growing strawberry bushes. He purchases two different brands of tarps from a local store. Leo applies brand A to an area of the yard that receives full sunlight and brand B to another area of the yard that is in partial shade. He waters both areas daily. At the end of the study, Leo concludes brand A is more effective in growing strawberry bushes. Is Leo's conclusion valid? Explain why or why not