Which of the following events separate geologic time into eras and periods?
the creation of new ocean ridges
the appearance and disappearance of volcanoes
the appearance and disappearance of groups of organisms
the number of earthquakes occurring at that time

Combine like terms. do not forget to use the distributive property to simplify the first term. 2(3y + 5k) - 2k

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 must happen for new french words to be published in official dictionaries? a. they must be approved by the french academy b. they must be voted on by the people of france c. they must be used by famous french writers d. they must be used by philosophers a. they must be approved by the french academy