This is the 16754th most frequent Korean word.
사회가
"사회가" means "society" or "the society" in English when used as a subject.
In this sentence, '사회가' refers to society as a subject experiencing change.
사회가 변하면 사람들의 가치관도 변화합니다.
When society changes, people's values also change.
Here, '사회가' is again used as the subject, focusing on society's complexity.
사회가 복잡해지면서 해결해야 할 문제들도 늘어나고 있다.
As society becomes more complex, the problems to solve are also increasing.
In this usage, '사회가' indicates society as the subject responsible for sustainability.