That should be the cell membrane. The cell membrane acts as a filter in and out.
The answer is A: phytoplankton provides nutrients to consumers in the ecosystem.
Hope this helps:)
Aquatic environments, mainly the sea.
Answer:
I think it might be the last response, since it takes about what some say, 550 million years...
It might be wrong... But take it into consideration that it might be the right answer.
The researcher could look for the presence of proteins, because viruses have a envelope (capsid) composed of proteins that involve their genetic material. The capsid may have a helical or icosahedral structure and is extremely regular. Viroids cannot synthesize any type of protein, so differentiation is possible.