Question

question
why is phenol red added to the test tubes?
phenol red is a ph indicator.
phenol red participates with the light reactions of photosynthesis.
phenol red provides carbon atoms for photosynthesis.
phenol red detects the release of oxygen.

Explanation:

Phenol red is a well - known pH indicator. It changes color depending on the acidity or basicity of the solution. In experiments, it can show changes in pH which may be related to chemical reactions occurring in the test tubes, such as those involving the uptake or release of substances that affect pH. It does not participate in photosynthesis light reactions, provide carbon atoms for photosynthesis, or detect oxygen release.

Answer:

Phenol red is a pH indicator.