Which rock layer (by letter) is the youngest and the oldest? Then, order each layer by oldest to youngest.

Which of there factors contributed most to us westward expansion in the second half of the nineteenth century?

Can someone list any possible solutions to air pollution ?

Rectangle qrst is shown. angle qrt is congruent to angle str, and angle str is complementary to angle qtr. which statement is true about angles qrt and qtr? they are congruent. they are complementary. they are supplementary. they are right angle