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Ally wants to figure out how salt affects the growth of plants. She gathers 30 ferns and puts them on her window sill. She waters them the same amount each day. She give 10 ferns 10 g of salt, 10 ferns 5 g of salt, and the 10 ferns no salt. These are her control group AND her constants
What is control group: 10 ferns with no salt? What is the constants are same plants, same amount of sun, and same amount of water?