introduction of a non-native species reduced daylight hours during winter preventing the cutting of trees in forests riverbank erosion resulting from springtime flooding
I gave my students this multiple choice question: Which of the following is most likely to disrupt the natural balance in an ecosystem?

Only one answer is correct among these 4 choices:
- introduction of a non-native species
- reduced daylight hours during winter
- preventing the cutting of trees in forests
- riverbank erosion resulting from springtime flooding

Could you tell me which one is correct?

introduction of a non-native species