,21. wood storks use their long beaks to feel around in shallow water until they find small fish, which they snap up and eat. their feeding style is dependent on the natural flood and drain cycles of the everglades. populations of wood storks in the everglades declined from an estimated 4000 pairs in the 1930s to about 250 pairs in the 1980s. which human activity has contributed most to the reduction of wood stork populations? building structures on stork breeding grounds building channels to control water flow in the everglades using stork feathers in clothes disturbing storks while boating hunting and sightseeing in the area

Option B, building channels to control water flow in the Everglades

Explanation:

The nesting pattern of wood storks is highly dependent on the pre drainage condition of Everglades region.

However in Everglades region several canals, ditches and roads have been constructed in recent times due to which the drainage pattern and wetland fragmentation is disturbed through out the region. This has lead to the reduction in the nesting activity of Wood Stork across the Everglades which has ultimately caused reduction of wood stork population.

Hence, Option B is correct.

it has to be understood that the sea water contains a huge amount of sodium and chlorine ions and if they enter the cell of the atlantic cod fish, the cell will shrivel and the fish will die. to avoid such a condition, the fish uses active transport for the purpose of removing the ions against the gradient.

explanation:

the atlantic cod is not a maritime osmoconformer. its native application of salts is less than that of the seawater it lives in. it is continually falling water from the gills to the ocean via osmosis.

countering that, the fish is going to be swallowing seawater. but since its internal collection of salts is lower than seawater, the fish will want to go free of excess salt, and since that's going upon a gradient, then active transport, requiring energy, must be used to pump out the salt. much marine fish use the organs to filter out the salt and these fish discharge very straight urine.