9. A climax community will persist until it is altered by-
A) a major change in an abiotic factor
B) seasonal dieback of vegetation
C) the reappearance of lichens and mosses

the national environmental policy act (nepa) is a united states environmental law that promotes the enhancement of the environment and established the president's council on environmental quality (ceq). the law was enacted on january 1, 1970. to date, more than 100 nations around the world have enacted national environmental policies modeled after nepa.

some scientists like gregory adcock agree with thorne's theory of regional continuity.

others, like chris stringer and ian tattersall, believe thorne's results may be contaminated or misinterpreted.