True.
In the upper layers of the atmosphere, it blocks UV radiation from the sun; however, in the lower layers, it is a pollutant.
I am not sure if this question means the adjective form or the adjacent form? However, a Schwann cell is a type of glial cell and its main function is to support neurons. Adjacent to the Schwann cell are nodes of Ranvier which are gaps in the myelinated axons, and are believed to assist in potential generation among other things.
Answer:
i think its b or c not sure exactly good luck
