Question

which statement best describes the effect of the eruption of mount saint helens?
ash clouds blocked out the sunlight, and the ash covered everything on the ground.
the eruption disrupted prevailing wind patterns.
buildings, bridges, and roads collapsed due to major widespread flooding and mudflows.
the eruption caused the erosion of rocks into tiny fragments.

Explanation:

The 1980 eruption of Mount Saint Helens released massive amounts of volcanic ash. This ash formed dense clouds that blocked sunlight over large areas, and falling ash blanketed the ground, vegetation, and structures in the surrounding region. The other options are either incorrect or not the most defining, widespread effect: wind patterns were not a primary disrupted effect, flooding/mudflows were localized secondary impacts, and rock erosion into fragments is not the key signature effect of this eruption.

Answer:

Ash clouds blocked out the sunlight, and the ash covered everything on the ground.