El niño is caused by
a. ocean currents
b. the isolation of continents
c. orography
d. all of the above

El Nino is caused by ocean currents. The correct option among all the options that are given in the question is the first option or option "a". The phenomenon of El Nino occurs after every three to five years. I hope that this is the answer you were looking for and it has come to your help.

Developed countries will see a decrease in natural resources, because their population will decrease.