Answer : The balanced chemical equation will be:
(i) 
(ii) 
Explanation :
Balanced chemical equation : It is defined as the equation in which total number of individual atoms on the reactant side is equal to the total number of individual atoms on product side.
Part (i):
The balanced chemical equation will be:
This reaction is a single displacement reaction in which most reactive element (potassium) displaces the least reactive element (hydrogen) form their solution.
Part (ii):
The balanced chemical equation will be:
This reaction is a single displacement reaction in which most reactive element (zinc) displaces the least reactive element (magnesium) form their solution.
Answer:b. gravitational, kinetic, thermal
Explanation:
The above explains the mechanism of the core forming process on earth/planet.
It is believed that this process might has contributed significantly to a planet's early stages heating. The time when these core-forming event happened is thought to have been mainly completed very early when Earth was young . The type of this event rather than it being seen as a single catastrophic event, it is likely to have been as a result of contractions on the earth severally.
The addition of partially differentiated material from another giant impact the rate of this spasm , and it increases each time the planet's mass is to increased.
This is a little on the history of planetary evolution.
