13. An intervening obstacle is a man-made feature that haits or slows migration from one place to another
А. True
B. False

I think that may be false, because intervening obstacles are not man-made, but instead things such as mountains or forests

This would be an open primary. a closed primary people can vote only prior to election day if the party if they are registered. independent voters can not participate. there is not a wide-open primary, but there is a semi-open primary.

Asmall closed hole formed in an outwash plain or moraine. forms when a  glacier retreats then remains stationary.