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: Dental
Agar is prepared from: 
Select and explain. 
A. Bullock heart, B. Chemicals, C. Seaweed, D. Chick cells
C: Seaweed
Answer: C: Seaweed 
Explanation: Agar, a polysaccharide extracted from certain types of seaweed, is the main active ingredient in the material, while water is the major constituent in the agar impression material.
Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, 12th ed page no 170