Answer:
It helps deal with stress, taking your mind on the task at hand. Trying something new can be fun and even productive around the house.
The number of synaptic vesicles are increased.
Interspecific competition I believe
Both parents must be carriers, which means they have the heterozygous gene (one uppercase letter & one lower case letter). They will still carry that mutated gene (because they have a lower case letter), and their offspring will have a 25% chance of getting a recessive disorder. The percentage is low but still possible.