Where would you be most likely to find the oldest rocks on earth?
in the middle of the highest mountains
in the middle of the continents
at the outer edges of oceanic crust
in the middle of the oceans

At the outer edges of ocean crust

Explanation:

The rocks found in continents are older and in some cases the oldest. The younger rocks are found in mid ridge of ocean. The oldest rocks can be found in ocean trenches that are very deep.

At the outer edges of ocean crust, oldest rocks can’t be found as relatively newer ones are formed continually and mostly found. So, different regions have different ages of rocks and needs to be explored properly.  

sodium i think the chemical element of atomic number 11, a soft silver-white reactive metal of the alkali metal group.

that would be called plucking : )

explanation:

''plucking, also referred to as quarrying, is a glacial phenomenon that is responsible for the erosion and transportation of individual pieces of bedrock, especially large "joint blocks". as a glacier moves down a valley, friction causes the basal ice of the glacier to melt and infiltrate joints (cracks) in the bedrock."