15. (1) what is an island arc? a. a large wooden boat that ferries animals from one island chain to another. b. a crescent shaped volcanic mountain chain created by plate tectonic volcanism. c. an anomalous electrical charge. d. none of the above.

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

Which statement about portugal is not true? a. it granted independence to its last colony in 1975 b. it has avoided conflict with spain c. it was a leader in european world exploration in the 1400s d. its economy is changing from agricultural to industrial b. it has avoided conflict with spain

Some of the incoming solar radiation is absorbed by the floor. identify the type of electromagnetic energy reradiated by the floor