Q.No.11: - By which interactions the quarks change their flavors?

Q.No.11: - By which interactions the quarks change their flavors?

Answer: - Quarks change their flavors only by weak interactions. By emitting or absorbing a W  boson. Any Up-type-quark (up, top, charm) change to any down-type-quark (down, bottom, strange) and vice versa.