The tickle syndrome (laughing in response to touch) and trembling ears (triggered by exposure to bright blue light) are both dominant traits in human beings.

(a) What is the probability that the first child of parents who are heterozygous for both the tickle trait and the trembling ears trait will have tickle syndrome but lack trembling ears?

(b) What is the probability that their third child will be a male who has neither tickle syndrome nor trembling ears?