Answer:
Its A ive done it before if you need proof here http://assessment.aaas.org/items/CE056001#/0
Explanation:
If the dragonflies consume autotrophs, then they are at the second trophic level. However, if they consume herbivores, then they are at the third or higher trophic level.
Need more information to determine.
Answer:
A concentration gradient must exist.
Explanation: