Aclass wants to find the ideal temperature for plants to grow in a terrarium. if the students set up several terrariums, what should they do to get the best results? a. plant different kinds of plants in each terrarium. b. use a light bulb with different brightness in each terrarium. c. add different amounts of water to each terrarium d. use different fertilizers in each terrarium

It would be B because you want to know which TEMPERATURE is the best for the plant. Different brightness for a bulb will give different amounts of heat. Since the amount of heat is your INDEPENDENT VARIABLE, you have to change the amount of heat for each plant, so the brightness of bulbs. Therefore, B is your answer!

sodium (na), for example, has one electron in its valence shell. this is an unstable state because that valence shell needs eight electrons to be full. in order to fill its valence shell, find a way to add seven electrons to its valence shell