4. In his science fair project, Julio did the following: He took 4 fish tanks and put 10 fish of identical size in each. Fish in tank 1 received 4 hours of light/day, fish in tank 2 received 6 hours of light/day, fish in tank 3 received 8 hours of light/day, and fish in tank 4 received 12 hours of light/day. At the end of 2 months, he measured the size of all fish and compared the fish in tanks 1, 2, and 3 with the fish in tank 4 because fish in tank 4 received the amount of light recommended by his teacher. what is the control?

h

explanation:

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."