Present-day food shortages are blamed on all the following except

its B just took the ;)

Explanation:

in 1803 the louisiana purchase took place, doubling the size of the country. by 1840 almost 7 million americans had migrated westward in hopes of securing land and being prosperous. the belief that settlers were destined to expand to the west is often referred to as manifest destiny.

explanation:

i believe the answer is the last option, the magyars preferred to invade by land.

i hope this ! : )