WHO HAS BIG BRAINS? not me... so please help? What is isostasy dependent on a balance between?

A.)the downward push of the mantle and the upward push of the continents

B.)The downward push of the ocean floor and upward push of the continents

C.)The downward push of the continents and upward push of the mantle

D.)The downward push of the ocean floor and upward push of the mantle

I'm kinda lost ! 1. when marilyn takes her pet dog for a walk, the dog walks at a veryconsistent pace of 0.55 m/s. draw a position-time graph to representmarilyn's dog walking the 19.8 m distance from the front of her house tothe nearest fire hydrant.2. both car a and car bleave school when a stopwatch reads zero. car atravels at a constant 75 km/h, and car b travels at a constant 85 km/h.a) draw a position-time graph showing the motion of both cars. howfar are the two cars from school when the stopwatch reads 2 hrs? calculate the distances and show them on your graph.b) both cars passed a gas station 120 km from the school. when dideach car pass the gas station? calculate the times and show themon your graph.3. the figure below shows the position-time graph showing a shopper'smovement up and down the aisle at a store.a) write a story describing the shopper's movements at the store.b) when does the shopper have a position of 6 m? c) how much time passes between when the shopper enters the aisleand when he gets to a position of 12 m? what is the shopper's averagevelocity between 37 s and 46 s?

Astone is thrown into a pond. what happens to the amplitude of the resulting waves as they get farther from the point where the stone hit the water? explain.

The pressure increases by 1.0 x 104 n/m^2 for every meter of depth beneath the surface of the ocean. at what depth does the volume of a pyrex (bulk modulus 2.6 x 1010n/m^2) glass cube, 9.8 x 10^−2m on an edge at the ocean's surface, decrease by 7.5 x 10−10m^3? explain the formula beyond this point: p=1.0x10^4, b=2.6x10^10, l=9.8x10^−2, delta v=7.5x10^−10. at some point l needs to be cubed. why p is divided by delta v?