too close to one another. receiving different amounts of sunlight. in soil with high humus content. receiving different amounts of carbon dioxide.
I gave my students this multiple choice question: Two identical plants are planted 3 meters apart. One plant is flowering, but the other is not. A student concludes that the plants are receiving an unequal supply of water. Another possible explanation the other plant is not flowering is that the plants are

Only one answer is correct among these 4 choices:
- too close to one another.
- receiving different amounts of sunlight.
- in soil with high humus content.
- receiving different amounts of carbon dioxide.

Could you tell me which one is correct?

receiving different amounts of sunlight.