Astrocytes play a critical role in normal function of the mammalian nervous system. Astrocytes regulate synaptic transmission and plasticity, protect neurons against toxic compounds, and support metabolically to ensure their optimal functioning.
My answer is B. highest to the lowest.
In organizations especially in the military, the one who gives the order usually comes from the top position. It is transferred from the next to the highest position and passed until it reaches the lowest in rank.
The answer is the table of contents because it tells you where to find every lesson that is in the book