Phenotypes (characteristics) NOT THE ALLELES
I hope this counts - cell wall! helps keep most materials out but allows specific materials to pass through. animal cells do not have a cell wall
I suggest you to provide some options, as it's quite difficult to answer your question. Here is your answer: A long bone is covered externally with a sheath called the
periosteum, whereas the marrow cavity is lined with the <span>
endosteum</span>
. I've attached the illustration to make it clear for you
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