It means that it is impossible to get something for nothing, or the idea that even if something seems free, there is always a cost, no matter how indirect or hidden the cost is.
Many people are willing to suffer in order for the greater good. They feel that if their efforts and suffering can improve the lives of countless people, then their suffering was worth it.
Hope this helps
In my opinion there isn’t, but maybe change warm to warmth in the first paragraph?
To fix the sentence, change "," after 2004 to ";" and remove the "and" before scientists. It makes the sentence sound better.
I hope that helps!
