infected mosquitoes landed on socks three times more often than uninfected mosquitoes. Explain how this information can be used to reduce the spread of malaria

Possibly increase the production of socks

Explanation: As it implies, the mosquitoes that have sickness land on socks more often. Based on this information, since we know that malaria comes from mosquitoes, we can increase the production of socks, as that will separate most of the infected mosquitoes with the other mosquitoes, as most of the infected ones will fly over to the sock. With this scenario, we can bait the mosquitoes and know which ones are infected

"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."