I'm pretty sure that it's C. I'm not quite sure though.
D) Ecological systems often remain in balance if only one factor is altered.
Ecological system can affect one another regardless of how small or great the factor that was altered. This can have gradual and insidious effects on the ecosystem. <span>Ecosystem is
encompassing all the life on earth in the physical environment that
supports it. An ecosystem involves both the biological (plants, animals,
human beings) and non-biological (land, water, soil, and atmosphere)
community which interacts as a system. More importantly, the living
things are very dependent on the abiotic community since it cannot
survive by itself.</span>