Easy points, put this in simple English that i can understand( this is for phycology) : if you place a toy under a blanket, the child who has achieved object permanence knows it is there and can actively seek it. At the beginning of this stage the child behaves as if the toy had simply disappeared.

So you and your partner don’t get sexually transmitted diseases and so your partner doesn’t get pregnant

Answer (185 billion dollars).

This is first hand knowledge, top-level athletes, successful business people and achievers in all fields all  set goals. setting  goals  gives you long-term vision and short-term motivation . it focuses your acquisition of knowledge, and you to organize your time and your resources so that you can make the very most of your life.