From which location does seafloor spreading originate?
mid-ocean ridges
edges of continents
deep-ocean trenches
underwater volcanoes

Mid Oceanic Ridge (MOR) to Deep-Oceanic trench

Explanation:

Explanation:\ As the plate tectonic theory is a continuous process, so at some places, divergent plate movement takes place whereas at other places, convergent plate movement takes place. So from that context we can conclude that initially two plates moves apart from each other,

   and this plates then collides with the other nearby plates, thereby the heavier one gets subducted beneath the other, forming a deep sea trench.

From mid ocean ridges seafloor spreading is originated. Hence the answer is option A

Explanation:

Sea is the smallest form of ocean. Geographical sea is defined as a water body which is partially enclosed by land. Sea occurs in area usually where oceans and sea meets. Sea is also less deep when compared to ocean.  

The water of sea is salty whereas the water of rivers, lakes are freshwater. Mediterranean, The Caribbean Sea, Bering Sea, etc are common example of sea. Seafloor spreading occurs due to the movement of tectonic plates under the ocean.  

the correct answer is c   with the systems