Water quality testing would be the best approach.
The answer is number 3 use this to help you : https://quizlet.com/118565169/nsg-6005-week-8-flash-cards/
Answer:
In this simple food chain, the organism that converts solar energy into usable chemical energy is missing. That would be the producer
Explanation:
Only producer which is the plant make use of sunlight and convert it to chemical energy for production of food