page 12 16. The list describes some uses of stem cells. 1 Studying how cells differentiate 2 Researching the development of Parkinson’s disease 3 Producing skin for skin grafts 4 Bone marrow transplants Which of these uses are not therapeutic? A 1 only B 1 and 2 only C 2 and 4 only D 3 and 4 only 17. Which of the following is an example of sexual selection? A Koalas with resistance to disease surviving to reproduce. B Peppered moths with the most effective camouflage avoiding predation. C Plant breeders selecting barley cultivars to cross to improve grain yield. D Female black grouse mating with the male with the best display.