Score points! The answer is satisfactory and another 100 points are added We drain the most thing

The toilet --- discharged from the sewer pipe --- septic tank--- and then discharged through the sewer to the sewage treatment plant--- and then discharged to the rivers, lakes and seas--- evaporate into water vapor--- rise to the sky--- become clouds--- more and more, and then become rain--- rain, so it falls into the soil --- becomes fertilizer, so that the crops grow better--- crops grow for us to eat--- after eating, continue to the toilet to drain the --- cycle ......

In the soil, this is a good fertilizer... In the countryside, people would water it in vegetable fields...

In fact, this world is reincarnated. You ate it and pulled it. You pulled it and ate it.

It's going to be in the river.

Toilets--- sewer pipes--- septic tanks--- sewer sewers--- sewage treatment plants.

There are also places where manure trucks are pulled, which are pulled to the countryside to make fertilizer as organic fertilizer for crops.

There are also places that are not well managed, and they are directly discharged into the river.

Never looked into this.

There is depth to the problem.

It is estimated that if you ask an academician of the Chinese Academy of Sciences, he may not say it.

Can you be specific, even people who have seen it can't remember it.

It's back to me. It's disgusting, but you can go back if you keep thinking about it.