The answer is organic farming.
        
             
        
        
        
Answer:
A group of bacteria that accumulate in layers and secrete a protective extracellular material. (Option A)
Explanation:
Biofilm is defined as one or more types of microorganisms collectively grow in different places. Organisms that form the biofilm include protests, fungi, and bacteria. 
Dental plaque is an example of a biofilm. It is a known buildup of slimy bacteria that forms on the teeth surface. Biofilm can grow on different surfaces such as animal tissues, plant tissues, minerals, metal, etc.
 
        
             
        
        
        
Cell specialization allows new cells to develop into a range of different tissues, all of which work together to make living organisms function as a whole. The process of cell specialization exactly how cells develop into their diverse forms is complex.
        
             
        
        
        
Phylum. The classification system goes: Kingdom, Phylum, Class, Order, Family, Genus, Species. Anything that shares a class also share anything above it.