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.
Answer:
26%
Explanation:
if cytosine makes up 24%, then guanine also makes up 24%.
add these to get 48%.
subtract that from 100% to get a remaining 52%
then split the 52% between adenine and thymine to tell you that 26% is thymine
Answer:
FF | FA
-------------
FA | AA
Explanation:
F= free ear lobed male A= female with attached earlobes
FF | FA
-------------
FA | AA
The first step of DNA replication is the separation of the two DNA strands to create a replication bubble. DNA Helicase is what breaks the hydrogen bonds joining the two strands, allowing it to unravel.