Which of the Following Statements About Dinoflagellates Is True

Multiple Choice

Which of the following statements about dinoflagellates is true?

A) They possess two flagella.
B) All known varieties are autotrophic.
C) Their walls are usually composed of silica plates.
D) Many types lack mitochondria.
E) Their dead cells accumulate on the seafloor, and are mined to serve as a filtering material.