The Arabian Desert covers much of North Africa?

Which german count invented the zeppelin

What do most climatologists see as a major cause of rising global temperatures? a. earth's closer proximity to the sun due to its gravitational pull b. greenhouse gases produced by burning fossil fuels c. rising ocean levels caused by melting polar ice sheets d. water pollution cause by industrial waste

After studying the timeline above, what observations can you make about u.s. environmental policy between 1970 and 1996?