3. There was a drop in the rate of motor vehicle deaths between 1950 and 1975 and then again between 1975 and 2000. What factors can you think of that may have caused these drops?

Seat belts and airbags were inserted into cars around the time of the late 1950s so the rate of death during a car accident would decrease because people are more likely to survive. And then in 1991 Side Impact Protection System (SIPS) was placed into cars again reducing fatalities during a car incident as people became more protected. :)

Iwould say overuse ( but not 100% sure ) in the u.s. we tend to overuse water by leaving it running, throwing it away, taking long showers, etc.