Answer:B
Explanation:
Given
Distance of astronaut From asteroid x is 
Distance of astronaut From asteroid Y is 
Suppose M,M_x,M_y be the masses of Astronaut , asteroid X and Y
If the astronaut is in equilibrium then net gravitational force on it is zero
cancel out the common terms we get
If you look on the periodic table you will see the top group elements depending on how the elements relate to each in the column. All of the elements in that column show they all have 1 electron in their valence shell. Some of the chemicals in that family or group are Sodium, Lithium, Potassium. The are very reactive because they only have one electron and what 7 more to become stable.
I believe the answer is b) slowly heating the surface
<span>The Earth’s internal "((HEAT))" source provides the energy for our dynamic planet, providing it with the driving force for on-going disastrous events such as earthquakes and volcanic eruptions and for plate-tectonic motion. </span>
