Option B. A man pushes a couch across the room is the answer.
        
                    
             
        
        
        
A heterogeneous mixture is a mixture of substances. In this mixture, substances are not chemically bonded just mixed, they're only together.
Examples:
A bowl of different nuts - Many types of nuts together.
A puddle of mud - Water, sand, leaves
Dirt - a bunch of particles held together.
Hope it helped1
        
             
        
        
        
1) Carbohydrates—> monosaccharide (sugar)
2) Lipids —> fatty acid 
3) Proteins —> amino acids
4) Nucleic Acids —> nucleotide
        
             
        
        
        
Flat bones have two thin layers of compact bone which is surrounded by a layer of spongy bone.