Anyone know? Help need answer ASAP!!

Drastic boundary changes can occur for all of the following reasons except for a. a shift in the way a river flows b. the collapse of a government system c. a conflict between two neighboring groups d. one country's decision to sell land to another country select the best answer from the choices provide

Why is the study of demography important to geographers

Which events occurred during the space race? check all that apply. (a) nasa was established. (b) yuri gagarin orbited earth. (c) the soviet union launched salyut. (d) the united states launched skylab. (e) the united states launched explorer 1.