True. If the amount displaced is more than the mass, it floats. If the amount is less than the mass, it will sink.
D. Is repelled by a magnet
When you hold a spinning wheel, the wheel and you, chair included, form a system that obeys the principle of "conservation of angular momentum". This means that any changes in angular momentum within the system must accompanied by an equal and opposite change, so the net force is zero.
There are 100 billion planets
Protons, electrons, and neutrons. The nucleus (center) of the atom contains the protons (positively charged) and the neutrons (no charge).