Name the cell type responsible for
myelination in the CNS

oligodendrocytes

Explanation:

oligodendrocytes wrap themselves around axons to create a myelin sheath. These are the 2 cells responsible. Outside the nerve are Schwann cells.

ok will do i shall do that now

answer:

i don't believe the ocean is purple, but it might once have been:

as for the sky, according to nasa:

"sunlight reaches earth's atmosphere and is scattered in all directions by all the gases and particles in the air. blue light is scattered more than the other colors because it travels as shorter, smaller waves. this is why we see a blue sky most of the time."