Location where two rivers meet, this makes trade

In the following diagram, four different index fossils are labeled: which of the labeled fossils comes from the oldest organism? a b c d

How does central place theory explain patterns in the size and distribution of cities?

Which part of a mountain receives the majority of moisture due to the rain shadow effect? a. the leeward side b. the windward side c. the bottom of the mountain d. all parts of the mountain receive equal amounts of moisture.