Vaccine, bacteria, pathogens, cells, toxins, antibiotics. In that order vaccine being first
        
             
        
        
        
Answer:
they tend to run more smoothly and on schedule;
not having a human on board to deal with unexpected problems
Explanation:
I just had the same one 
 
        
             
        
        
        
Answer:
Fight or flight response.
Explanation:
Fight or flight response is also known as hyper arousal response. This response is mainly generated in case of attack and harmful event. 
Jade hears a rattle sound and sees a rattle snake as she turns turns around, this is a type of harmful event or fear for Jake. This condition causes the dilation of pupil, sweat and heart pounds in Jade's body. The fight and flight response has been generated in Jade's.
 
        
             
        
        
        
Explanation:
Well, one could use a magnet to see if it's ferrous. One could melt it to check which type it is, use a metal detector, or just use their senses: If it dings or clinks like metal, and feels like it’s texture. If it polishes with metal polish, is reflective, can be shaped or shape when heated… It usually is a metal. If it rusts, or oxidizes, it is or contains metal. If it “smells" like metal, most likely, it is metal. Finally, if it walks like metal, and quacks like metal, most likely we have a metal