The answer is C. Organized, follows a pattern
Structured Exercise is an activity in which someone has to follow a specific plan to achieve a specific fitness goal. In order for the structured exercise to be successful, the participant has to undergo an organized training schedule that target a specific result. 
        
                    
             
        
        
        
Most diseases can't be passed from person to person
        
             
        
        
        
Our body needs some kinds of bacteria to maintain a balanced and healthy state. for example, our bodies need Lactobacillus acidophilus to create lactic acid which is the acid in our stomachs/intestines. without it, we wouldnt be able to properly digest our food. 
there are some cases in which bacteria can be really harmful however like salmonella which, odviously isnt ideal for our bodies. even good bacteria can hurt us if we end up with to much of it. 
this isnt a super detailed explaination but i hope it helped!