Im going to remember this everytime someone asks me if I am a glass half empty or half full kinda person - My answer is going to be "Depends on which way round the fish is!" Which will make sense to no one who hasn't seen this image.
Retroviruses are another type of virus. They have RNA instead of DNA. They infect cels and make them make copies of the virus until the cell bursts and spreads the virus. AIDS is a result of the retrovirus HIV