Help please 10 points

Which quantities decrease as the distance between a planet and the sun increases? check all that apply.

How did the completion of the transcontinental railroad change the lives of american citizens? a-it increased the wealth of all americans and enabled them to travel more.b-it made cross-country travel too expensive for ordinary americans.c-it decreased the safety of americans who moved to settle the plains.d-it shortened travel time between the east and west for all americans.

Characteristics of what type of economic system are being described below? 1.economy in which some/all of the basic economic questions answered by central authority 2.trade generally limited to what is produced through the influence of the government a.command economies. b.market economies. c.traditional economies.