The Earth's crust is principally composed of . A. Granitic and sedimentary minerals b. Granitic and basaltic minerals c. Basaltic and sedimentary minerals d. None of the above.

i think the answer to your question is: settlement of the interior and economic growth. ( ^_^)／

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.