Which one of the following is not a cause for urban migration?
a)
to operate of machines used in manufacturing factories
b)
to get employment as drivers for construction trucks used to build the roads in a city
c)
manual jobs in the manufacturing industries within a city
d)
search for suitable land for agriculture

The option which is not responsible for the cause of urban migration is the search for suitable land for agriculture. Hence the answer is option D.

Explanation:

The land for agricultural use is available in rural areas and it is not available in urban areas. The land in urban areas is suitable for infrastructure and buildings and houses. Hence there is no land available for the agriculture purpose.

Also, we know that there is much pollution in urban areas which is not suitable for the growth of crops. In rural areas the atmosphere and all the condition is favorable for the growth of crops. Hence, we can see that it is not a cause for migration to urban areas.  

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.