Billy decides to test the factors that affect plant growth. He uses sunflowers, daisies, and bean plants. He gives some of the plants fertilizer and other plants only water. He plants the sunflowers in a garden outside but plants the daisies and bean plants in small containers inside his house. He measures the height of the plants each day using a ruler. What is wrong with Billy’s experiment? There are too many responsive variables.
There are too many manipulated variables.
There is nothing wrong with the experiment.
There are too many controls.

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.