Answer:
1. Oak tree and grass (not sure ahahahha)
According to the pyramid energy, the energy content is maximum in autotrophs or producers
2. Robin, chipmunk, mouse
3. oak tree and grass
4. 0.9kj
5. the hawk population will experience a greater impact than the fox population in this ecosystem because there is only two animals which are mouse and chipmunk that can consumed by hawk. For the fox, there are 4 type of animals to consume which are cricket, chipmunk, rabbit and mouse. Hawk consume less type of animals thus it will experience a greater impact compared to fox