This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Forensic Medicine
Diatoms are - 
Select and explain. 
A. Algae, B. Parasites, C. Bacteria, D. Fungi
A: Algae
Answer: A: Algae 
Explanation: Diatoms are unicellular algae.