Final answer:
The sediments on the ocean floor are thinnest at the mid-ocean ridges and thickest near the continental borders, due to the age of the seafloor and the accumulation of sediments over time.
Step-by-step explanation:
Due to seafloor spreading, the sediments on the ocean floor are thinnest at the crest of the ocean ridge and thickest near the continental borders.
Sediments are constantly being added to the ocean floor primarily through the processes like erosion and runoff from continents. The closer to the mid-ocean ridges where new crust is formed, the thinner the sediment layer is because it is youngest and has had less time to accumulate sediments.
As you move further away from the ridges towards the continental margins, the ocean floor is older and has had more time for sediment accumulation, leading to thicker sediment deposits. This phenomenon is a direct result of the oceanic crust moving away from the mid-ocean ridge due to the creation of new crust at these divergent boundaries.