The answer for this question would be Integument, digestive, respiratory and urogenital.
The largest system that contact with the external environment would be integument and digestive. That makes two system has normal flora of microbes and not sterile like the other systems. Normal flora of microbes will prevent the pathogen microbe grows so it gives some benefit.
No se Emile no w ye no se
First Blank Space:Flourens
Second Blank Space:Broca
DNA fingerprint is a pattern of dark bands on photographic film that is made when DNA fragments are separated by gel electrophoresis and tagged. The photograph produced is often used to determine whether or not suspects were involved in a crime.
hope this helps!