Answer:
1. Cellular level refers to a degree of organism complexity, which is either colonial or unicellular.
2. Homeostasis refers to the comparatively steady state in the internal environment of an organism.
3. Feedback loops are the self-regulation approaches, which transmit information to a suitable physiological system so that appropriate amendments can be done.
4. Negative feedback refers to a control mechanism, which counteracts or prevents the previous reaction.
5. Positive feedback refers to a control mechanism, which enhances or augments the previous reaction.
6. System-level refers to the extent of the complexity of an organism, that is, the cells organized into systems.