12 of 19 Page 11 of 21 10. (8 marks 2+2+4) About 30% of human twins are identical, and the rest are fraternal. Identical twins are necessarily the same gender (half are male-male and the other half are female-female). One-quarter of fraternal twins are male- male, one-quarter female-female, and one-half are mixes: one male, one female. a. Name two, non-complementary, events related to this situation. b. Show this information on a tree diagram. c. You have just become a parent of twins and are told they are both girls. Given this information, what is the probability that they are identical?