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.
No one really knows for sure. We do know that allergies play a role in many people with asthma but not in all. As with allergy, you can blame your family history, as there is a strong genetic component for asthma. If you or a loved one has asthma, it's important to understand the many asthma triggers.