This term is generally used to describe producers of illegal drugs in latin america who band together to keep the prices- and supply- of those drugs at high levels.

a) cartel
b) clan
c) monopoly
d) oligopoly

answer; (d) melting of sea ice;

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.