What primarily set off large-scale migration flows among European countries during the twentieth century? A. the ability to establish distinctive political structures
B. the familiar cultural traditions of the host countries
C. the motivation to reach quotas set by individual countries
D. the desire to reunite with family members who migrated previously
E. the removal of migration restrictions

D) the desire to reunite with family members who migrated previously

Explanation:

i took the test

the correct answer is - end permian.

the end of the permian was marked by the biggest mass extinction out planet had ever witnessed, so no wander that this period has been given the nickname of ''the great dying''. around 96% of the species died out, and it was caused by multiple natural catastrophes, including massive super volcano explosions and lava flows, huge amounts of co2 released into the atmosphere, as well as methane from the algae, and that contributed to acidified and stagnant oceans. it is thought that it set life on earth backwards for about 300 million years.