Predation
It can be explained in that way or also called Predatory/prey relationships.
Parasitism is when one is benefited and the other harmed (ie leech and human)
Commensalism is when one is benefited and the other not affected (Tree frog and rainforest tree)
Mutualism is when both are benefited (Bee eats honey and Flower is pollinated).
La Niña follows after an El Niño. Its sea surface temperature will be lower than the natural one by 3-5 degree Celcius which tells us that it is cooler than the average temperature. It is the positive state of the El Niño. It really disturbs the natural weather patterns which could result to extreme storms.
That would be death if you are referring to the human growth cycle