What lines of latitude determine the" tropics"? My answer is 23.5 degrees N and 23.5 degrees S latitude. Am I right?

Please check me on one more! Why is Greenwich, England, so important to a geographer? My answer is -- Because the prime meridian runs through it. Am I right?

Correct -- for both questions.

http://www.google.com/search?rlz=1C1GGGE_enUS379US379&gcx=w&sourceid=chrome&ie=UTF-8&q=latitudes+for+tropics

23.5 north and 23.4 south

Name at least 2 items a maps key should include

Yes, you are correct on both counts!

The lines of latitude that determine the "tropics" are indeed 23.5 degrees north and 23.5 degrees south. These lines are known as the Tropic of Cancer (23.5 degrees north) and the Tropic of Capricorn (23.5 degrees south). These lines mark the northernmost and southernmost boundaries, respectively, where the sun can appear directly overhead at some point during the year. The areas between these latitudes are referred to as the "tropics" and generally have warmer climates.

Regarding Greenwich, England, you are also correct. Greenwich holds great importance to geographers due to the fact that the prime meridian runs through it. The prime meridian is an imaginary line that serves as a reference point for measuring longitudes around the world. It is designated as 0 degrees longitude, and all other longitudes are measured east or west from this line. Greenwich was chosen as the location of the prime meridian during an international conference held in 1884, making it a significant landmark for geographers and a crucial reference point for navigation and timekeeping.