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.
This produces an allergic reaction that takes the form of a rash, tiny blisters or, rarely, some other type of skin eruption. Sun allergies occur only in certain sensitive people, and in some cases, they can be triggered by only a few brief moments of sun exposure. Scientists do not know exactly why some people develop a sun allergy and others do not. There is evidence, however, that some forms of sun allergy are inherited.