The smallest structural unit of an organism that consists of one or more nuclei, cytoplasm, and various organelles is called a organ system

organ

tissue

cell

cell

Explanation:

hope this helps

i think the answer would d

sorry to break it to ya but no one can answer your question it's just

jk but i am serious about the part that most people cant answer it beacuse you did not mention the section you are talking about. but it would if you added some detail and were a bit more specific.