Answer:
The change in the ocean's temperature and salinity happens as we move further to the north and south of the equator. The reason for this is the icebergs and massive ice sheets. Icebergs after separating from the glaciers float in the oceans and start to melt. They provide cold and freshwater, lead to a change in the ocean. Antarctica and Greenland are the providers of the icebergs in the world.
Seems very basic, the ocean is above the plate, the plate material is heavier than water (it being rock). That's pretty much all of it. The plates grind a little and new land pushes up at plate boundaries but this does not seem to be related. The heavier material is below and the lighter above, those being rock and water respectively.
You didn't give your choices but sin 21 equals 0.358.
Answer: expanding
Explanation: the universe is still expanding
