A:True because Lithium is the lighest solid and metal and the third lightest element.
Yes, it is because gravity is a force of attraction to the center of our planet, Earth. If we drop a pencil, the pencil will go on the floor. Gravity is pulling the pencil down.
So that we do not contaminate it with microorganisms or garbage or other human stuff.
PH of 4 is Acidic and its property is to turn blue litmus red
