The most frequently used portal of entry for pathogens is the
A) mucous membranes of the respiratory tract.
B) mucous membranes of the gastrointestinal tract.
C) skin.
D) parenteral route.
E) All of these portals are used equally.

the answer is: metamorphic rocks often show the presence of fossils, also a

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-lavira: )

oxygen = 21% of the atmosphere

nitrogen = 78%

carbon dioxide = 0.1%

argon =0.934%

it marks things for degradation via the proteasome. it alters there celluar location.