The Answer is: C
Because of the volume that is already set by the size and weight of the container. In other words the gas is pushing all particles out of the way and replacing its self therefore the pressure increases.
Cells make up the tissues which combine to form the organs and then different organ systems make up the organism
so it's cells-tissues-organs-organ system-organism
Chemical reactions occur when chemical bonds between atoms are formed or broken. If this is what you mean because the question is really confusing sorry :(
