Which of the following is not one of the major principles of ecology?
a) the ecosystem will break down if energy and matter are not constantly supplied or recycled.
b) ecological systems and interactions are best understood by a thorough knowledge of the living and nonliving environments.
c) living things affect other living things.
d) ecological systems often remain in balance if only one factor is altered.

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. 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.