Answer:
I would believe the mesosphere would be the most difficult layer to breathe. Troposphere is where we are, ov we can breathe here, stratosphere would be hard to breath in as well
The answer to 3 is B. Moon
The answer is : linea aspera
E Coli bacterium are about 2.0 micrometers in length and .25 to 1 micrometer in diameter. In comparison, a red blood cell is about 6 to 8 micrometers in diameter and a thickness that ranges from .8 to 1 micrometer in the center to 2 to 2.5 micrometers at the thickest point.
