Astronomers estimate that the runoff channels seen on Mars must be at least 3.9 billion years old. How do they estimate ages like this? a. by examining radioactive rocks from these channels returned to Earth by robot probes b. by counting impact craters in the regions containing these channels c. by looking for the erosion of these channels by the regular periods of rainfall that occur on Mars even today d. by measuring the height of the region in which the channels occur; on Mars, older regions are always lower in elevation e. guessing

This phrase from the declaration of independence and its primary author thomas jefferson can be used to justify which statement? a) jefferson thought this document could be used in his defense were he put on trial for treason. b) jefferson knew that the colonists' actions would have an international impact. c) jefferson believed that a bill of rights was necessary in the new government. d) jefferson was trying to show the king that the colonists were intellectuals.

What is the latitude and longitude (to the nearest degree) of the following cities? a. kansas city b. philadelphia c. reno d. minneapolis use the map to find the names of cities with the following coordinates. a. 30°n, 96°w b. 35°n, 95°w c. 26°n, 80°w d. 42°n, 88°w how many kilometers north of the equator is washington, dc? approximately how far north of houston is kansas city? use degrees of latitude to calculate your answer. show your work. which city is closer to greenwich, england: los angeles or xi’an, china (34°n, 109°e)? explain your answer. how many degrees of longitude separate las vegas from the international date line, which is at 180° longitude?

How far is a geographic second? a.) around 100 feet b.) around 1,000 feet c.) around 5,000 feet d.) none of the above