Examples of reflection. Plane wave, plane surface. The phase of the reflected sound waves from hard surfaces and the reflection of string waves from their ends determines whether the interference of the reflected and incident waves will be constructive or destructive.
The tendency to develop allergies is often hereditary, which means it can be passed down through genes from parents to their kids. But just because you, your partner, or one of your children might have allergies doesn't mean that all of your kids will definitely get them, too.
Allergies in general affect approximately 25% of the population. If one parent is allergic, there is roughly a 50% likelihood that the children of the parent will have allergies. If both parents are allergic, there is almost a 100% likelihood that the children will be allergic.