I believe the correct response would be B. Of humans.
An organ or group of specialized cells in the body that produces and secretes a specific substance, such as a hormone
It would better your city. The city would look way nicer and a lot of people would probably enjoy a recycling program. For the reasons of having reused items so the dump won't be as bad and it would give more jobs and be a healthy way of discarding old paper and bottles. It could easily help out your city. The recycling program would be a great idea and I hope it could happen.
I hope this is what you wanted.....
Homeostasis it is an organism's ability to keep a constant internal environment.
