which type of drug classification are addictive drugs that have an extremely relaxing effect on the central nervous system

Central nervous system (CNS) depressants are drugs that slow down brain activity, making them effective for treating many conditions. These drugs operate by affecting the neurotransmitter gamma-aminobutyric acid (GABA), which leads to side effects such as drowsiness, relaxation, and decreased inhibition.

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."