What was collectivization and how did it affect the Soviet Union?

What evidence does the writer give to support his argument about coral reefs? a) he speaks of the activities of coral polyps. b) he describes the composition of the great barrier reef. c) he emphasizes the ways in which coral reefs are fragile. d) he points out the ways that scientists do research on the reefs.

Over half of the african-american population in the united states live in

¿qué parte de la patagonia está en peligro de exinción por su sobrepesca?