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.

Martha has a deck of cards. she has lost some of the cards, and now the deck only contains nine spades, eleven diamonds, eight clubs, and twelve hearts. martha predicts that whenever she draws a card from the deck without looking, she will draw a club one-fifth of the time. which activity would best allow martha to test her prediction? a. randomly draw a card from the box and see if it is a club. b. randomly draw a card. then, continue to draw another card until all eight clubs are drawn. c. randomly draw and replace a card 120 times. then, observe how close to 30 times a club is drawn. d. randomly draw and replace a card 100 times. then, observe how close to 20 times a club is drawn.