How do population pyramids help people to understand population trends in a country?

Distance that lewis and clark traveled from st. louis to ft. clatsop near the pacific ocean.

This word for a bug or malfunction was popularized in the 1962 book into orbit by the mercury astronauts

What did the pattern of earthquakes in the wadati-benioff seafloor zones show scientists? a.) earthquakes occur where the ocean floor reaches its highest temperatures. b.) many earthquakes take place 700 kilometers below the seafloor. c.) slabs of ocean floor return to the mantle in subduction zones. d.) ocean - trenches cause earthquakes.