Aparticular type of rock formation is known to have a porosity of 22%. how much fluid could be present in 50 l of this rock?

Maybe you should get some from your teacher and learn more so you can get your grades up and maybe study a bit more

B. nuclear reactions could first occur.

Vander waals forces are inter molecular bonds that exist within molecules of the same substance. a water molecule is made up of oxygen and hydrogen atoms which share electrons between each other. the vander waals forces are forces that exist between multitude of different  molecules of water. dipole dipole forces is the type of vander waals force that exist in water. the oxygen atom which is more electronegative pulls the shared electron closer to itself thus generating a partial negative charge while the hydrogen acquire a partial positive charge. these two different charges causes attraction to occur in water molecules.