A dog retrieves the newspaper every day because...

answer:

there is no cure for hiv, although antiretroviral treatment can control the virus, meaning that people with hiv can live long and healthy lives. most research is looking for a functional cure where hiv is reduced to undetectable and harmless levels in the body permanently, but some residual virus may remain. most commonly hiv-antivirals are taken also known as nucleoside/nucleotide reverse transcriptase inhibitors (nrti's).

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."