Maybe they had to consider the habitat to make sure the habitat they were releasing the dragonflies into would be appropriate for the dragonflies.
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!
When two atoms combine, the overlap of their atomic orbitals produces molecular orbitals.
