It produces more food for the tree. It increases the nutrients in the soil. It releases more oxygen from the tree. It decreases the competition for resources.
I gave my students this multiple choice question: Some pine trees are able to live through forest fires because of their thick bark. After a forest fire, new pine trees can grow in the space left by other trees that burned down. How does thick bark help to increase the pine tree population?

Only one answer is correct among these 4 choices:
- It produces more food for the tree.
- It increases the nutrients in the soil.
- It releases more oxygen from the tree.
- It decreases the competition for resources.

Could you tell me which one is correct?

It decreases the competition for resources.