Pyroclastic flows primarily contain pumice, vesicular pyroclastic material, and .
a. ultramafic rock debris
b. a cloud of low-density hot expanding gases
c. low viscosity
d. lava flows volcanic mudslides called lahars

d. lava flows volcanic mudslides called lahars

Explanation:

Mudflows of volcanic eruptions are the most dangerous, and are called lahars. A lahar is a type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris, and water.

answer: a.letter a . . letter "correct answer"

b.letter c . . letter b "not b'

c.letter a . . letter b

d.letter b . . letter a

explanation:

the answer is c. according to past decisions, free speech is not unlimited.