There is variation in DNA.
I think it's A. They have a cell membrane.
Hope this helps!
<span>Silicon dioxide
forms the cell walls of diatoms. These diatoms are a group of algae.
Phytoplanktons are the most common types of diatoms that are unicellular. These
organisms can form colonies in the shapes of filaments or ribbons, fans,
zigzags, and stars that are perfect for monitoring environmental conditions,
particularly water quality in the past and present. </span>
