D. physical property
the bonds between molecules of mercury are breaking so it's physical and it's not changing the chemical composition of the substance
Answer:
No the given statement is not necessarily true.
Explanation:
We know that the kinetic energy of a particle of mass 'm' moving with velocity 'v' is given by

Similarly the momentum is given by 
For 2 particles with masses
and moving with velocities
respectively the respective kinetic energies is given by


Similarly For 2 particles with masses
and moving with velocities
respectively the respective momenta are given by


Now since it is given that the two kinetic energies are equal thus we have

Thus we infer that the moumenta are not equal since the ratio on right of 'i' is not 1 , and can be 1 only if the velocities of the 2 particles are equal which becomes a special case and not a general case.
The reproductive system because without that we would not exist , but the same thing could be said about any other systems but the reproductive system is the reason why were here today .
B- Same force
It’s b because force always acts in equal but opposite pairs.