What is the most important body system for maintaining homeostasis?

Are these strong bases, neutral, strong acids, weak acids or weak base household bleach (ph=12.6) fluid in a car's battery (ph of less than 1.0) milk (ph=6.7) stomach contents (ph=2.2) pure water (ph=7)

The response is the basis for vaccination. primary secondary tertiary none of the above

How does human environment effect the biosphere