Which advances helped increase China’s population? terrace farming
water wheels
curved-shaft plows
gunpowder

Gun powder

Experimenting with life-lengthening elixirs around A.D. 850, Chinese alchemists instead discovered gunpowder. Their explosive invention would become the basis for almost every weapon used in war from that point on, from fiery arrows to rifles, cannons and grenades.

new ideas form the base for the growth of the people.each time they try to develop, they may discover a new form or abilities of themselves this makes the people satisfied in living their life in a happy way.this makes sense that new ideas of people cn change their live.the ideas, if bring their best, they will be changing their present state.

Abortion would be the most interesting topic to me