An Earth scientist is testing how various soil mixtures affect plant growth. She begins with 10 soil types. For each mixture, she combines equel amounts of 2 soil types. How many soil mixtures must the scientist create in order to test all possible combinations of the 10 sol types?

Study the picture of the ocean. which is the best example of an organism’s niche shown in the picture? a. the environment contains several of the same species of coral. b. the shallow area of the ocean meets the needs of the coral and the fish. c. the ocean has fish and coral that live in the same area. d. the coral take in food from the water and provide shelter for the fish.