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
A. The hosts body could reject the transplanted stem cells
I found the attached image on the internet related to this question.
The solid arrows represent neuronal communication. The stimulus, the effects, and the flow of information is all done by receptors and synapses that send a signals across the body in order to have effective feedback responses promoting the homeostasis of the organism.
Access Control Points
They are restrictions points that enforce regulations and guidelines on decontamination when exiting the sites and ensuring adherence safety standards when entering the site. The regulation are usually, as standard practice, conspicuously posted at the Access Control Points.
Access Control Points are usually set up at the periphery of the Exclusion Zones, and ideally, there should be a separate entrance and exit Control Access Point.