Question

you can measure the ph and temperature of your ecocolumn. what else can you measure in your ecocolumn? dissolved oxygen sunlight

Explanation:

An ecocolumn is a model ecosystem. Dissolved oxygen is a key parameter to measure as it affects aquatic organisms' respiration. Sunlight is an external factor, not a direct measurable component of the ecocolumn's internal environment like dissolved oxygen, pH, or temperature.

Answer:

Dissolved oxygen