Question

read the text.
congress passed the clean water act of 1972 to address the serious environmental crisis of water pollution. in new yorks hudson river, levels of toxic bacteria were 170 times the level considered safe. oil floating on the the cuyahoga river near cleveland, ohio, burst into flames in 1969. factories were dumping pollutants into waterways, untreated sewage flowed directly into rivers, and untold numbers of fish were dying. the clean water act restricted discharges of pollution into the nations waters and authorized the environmental protection agency to enforce water quality regulations. it also provided money for sewage treatment plants. although the work to clean streams is ongoing, water quality today is much better than it
which organizational structure does this text primarily use?
problem - solution
sequential

Explanation:

The text first presents the problem of water pollution (toxic bacteria in Hudson River, Cuyahoga River fire, factory dumping, sewage flow, fish dying). Then it presents the solution - the Clean Water Act of 1972 (restricting pollution discharge, authorizing EPA, providing money for sewage treatment plants). This clearly follows the problem - solution structure. Sequential structure would present events in a time - ordered sequence without the clear problem - solution relationship.

Answer:

problem - solution