Answer:
A cold ocean current
Step-by-step explanation:
The coast of Peru and Chile are affected by a cold ocena current named the Humboldt Current, after the famous German Geographer.
This is a cold current because it comes from the shores of Antarctica, and flows north besides the coasts of Peru and Chile.
Because the current is cold, the air is not as moist as in other areas, which leads to a extremely low level of precipitation. For example, the Atacama desert, in Chile, is the driest place in the world.