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>
Hihi!
The answers are that there are bones in mammals and inside of echinoderms there are calcium rich plates! If you have any further questions please feel free to message me!
I hope I helped!
-Jailbaitasmr
With the pic we can say virus is lying in the border line
Antibiotic resistance is not an example of natural selection. Mutations may be a source of variation in any population of bacteria. When antibiotics are used at first, all the disease-causing bacteria are killed.