Which of these protects the earth from harmful radiation when found in the stratosphere but is a pollution at lower altitude?

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.

What can you learn about precipitation levels in south america from this map? brazil is experiencing a drought.it rains more in higher altitudes.peru received the highest level of rain.venezuela got less than 25 cm of rain. 

In a class of 20 students, what democratic form of governance makes the most sense