You didnt put the picture so we cant see
Hydrogen and hydroxide ions
Multiple choices :
A. test for chemicals that might poison fish and cause algae to grow
B measure the dissolved oxygen content in pond-water samples
C look for sources of pollution that may be affecting the pond
D measure the amount of light at various levels in the pond
Answer;
D. measure the amount of light at various levels in the pond
Fish in the pond feeds on the algae that grows in the pod.
Therefore; death of fish in the pond caused a large increase in algae populations.
Measuring the amount of light in the pond would not tell the student what caused the death of the fish in the pond.
I hope this diagram helps
