Answer:
Rock
Explanation:
Let's calculate the density of each object:
Rock:
Pencil:

Therefore the rock is denser.
I believe Erosion is the process most likely responsible for the removal of the missing parts of the rock layers. Erosion involves the physical action of surface processes that removes soil, rock, or dissolved material from one location on the Earth's crust, then moved away to another location.
Combustion=heat and light
decomposition=taking something away
single means one element changes
and double means two elements change l.
Mole ratio:
MgCl₂ + 2 KOH = Mg(OH)₂ + 2 KCl
2 moles KOH ---------------- 1 mole Mg(OH)₂
4 moles KOH ------------------- moles Mg(OH)₂
moles Mg(OH)₂ = 4 x 1 / 2
= 2 moles of Mg(OH)₂
molar mass Mg(OH)₂ = 58g/mol
mass of Mg(OH)₂ = n x mm
mass of Mg(OH)₂ = 58 x 2
= 116 g of <span> Mg(OH)₂</span>
hope this helps!