The orbits of the planets are coplanar because during the Solar System's formation, the planets formed out of a disk of dust which surrounded the Sun. Because that disk of dust was a disk, all in a plane, all of the planets formed in a plane as well.
http://curious.astro.cornell.edu/about-us/57-our-solar-system/planets-and-dwarf-planets/orbits/242-why-do-all-the-planets-orbit-in-the-same-plane-intermediate
Answer: Energy is absorbed, and kinetic energy increases
Explanation: Boiling is the phenomenon in which liquid is converted to gaseous state.
Thus in order to break the inter molecular forces of attraction present in a liquid, energy is required and thus the process is endothermic in nature.
As the molecules absorb energy, the kinetic energy of the molecules increases and they start moving faster and more randomly and convert into gaseous state.
The answer for the first question is A. Proton is the subatomic particles which adds most of the mass of an atom as well as the neutron since they have the same mass. Photon, on the other hand, is not one of the subatomic particles.