Which of the following is not a cause of current mass extinction
a recycling
b global warming
c pollution
d overharvesting wildlife

a recycling 

Recycling is the process of reusing old materials such as plastics, throwable goods and other materials to be utilized for other purposes. This practice helps safe the environment especially the current conditions. The global warming, pollution and deforestation are all destructive occurrences and are man-made.

The answer would be b. it is a learned trait