Option 1 states that shelves are absent close to plate boundaries. This is incorrect because shelves can actually be found near plate boundaries. The continental shelf is the gently sloping area of the ocean floor that extends from the continent`s edge to the continental slope. It is a part of a larger plate that is connected to the continental crust.

Option 2 states that continental shelves are highly sedimented. This is correct. Continental shelves tend to be covered with a thick layer of sediment that has been eroded from the land and transported to the shelf by rivers. This sediment accumulation creates a fertile and productive environment for marine life.

Option 3 states that continental shelves have abrupt falls towards the continental slopes. This statement is incorrect. In reality, continental shelves have a gradual slope rather than abrupt falls. This gradual slope gradually transitions to the steeper continental slope, which marks the boundary between the continental shelf and the deep ocean floor.

Option 4 states that continental shelves are rich fishing areas. This is correct. The shallow and nutrient-rich waters of continental shelves provide an ideal habitat for various marine species, making them important fishing areas. These areas are often heavily exploited for commercial and recreational fishing.

In conclusion, option 3 is the incorrect statement as continental shelves do not have abrupt falls towards the