Food webs normally start at the bottom and work their way up. Like the plants will be at the bottom, and then each level shows the animals getting bigger while losing energy. You continually lose energy as you work your way up an ecosystem, so normally there are only three or four levels. I hope this helps!
I think its anaerobic respiration
The best and most correct answer among the choices provided by the question is the fourth choice "<span>Measure the amount of energy in the phytoplankton and the amount of light entering the aquarium. Then measure the amount of energy in the phytoplankton after exposure to the light and determine the difference." </span><span>I hope my answer has come to your help. God bless and have a nice day ahead!</span>