Fish ladders are a stair-like structure that gives the passage to the migrating fish to get around a dam to their destinations. As dams are an obstruction to fishes like salmon that migrate in the river upstream to breed, fish ladders have been created to allow the fish to get to their destinations by providing a passage around the dam.
Thus, the correct answer is option A. Fish ladder.
A fish ladder is the name given to the canal or structure found some reservoirs or dams, that connects it with the current of the river. These systems were created to prevent fish from being trapped in the reservoirs and therefore, prevents fish are unable to find their food and live in the rivers. Additionally, fish ladders are the main way to guarantee fish can migrate to other places which is essential for natural biological processes such as reproduction. So, the correct answer is A. Fish ladders.
