If all of the sudden a virus, such as.... Zika spread it would decrease fertility rate. Another factor could be if the country was third world, since a lot of expecting mother's don't have enough money for proper treatment or food could definitely decrease fertility rate.
The Indian Ocean basin form the ring of fire.
Answer:
People are concerned because humans are pretty dependant on fossil fuels! Did you know 70% of Chinas electricity is Generated from Coal? Thats how dependant we are on Fossil fuels in just one short example,however Fossil fuels aren't bad they are great energy sources! :D Hope that helped ~Feel Free to mark brainliest~
Lots of apples but I think macintosh