After British explorers mapped the west and east coast of Canada, who filled in the middle?

explanation:

on august 6, 1945, just days after the potsdam conference ended, the u.s. bomber enola gay dropped the uranium bomb known as “little boy” on the japanese city of hiroshima. despite its devastating effects, japan didn't offer unconditional surrender right away, as the united states had hoped.

explanation:

since the crust is readily accessible, scientists have been able to perform hands-on experiments to determine its composition; studies on the more distant mantle and core have limited opportunities samples. so scientists also rely on analyses of seismic waves and gravity and as well as magnetic studies.