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.
1 It has to do with the relative ratios of lactose and the three casein variants in breast milk as compared to the milk of other mammals. 2  Breast milk is high in lactose but low in the caseins.) Also, be aware that once a single allergy is triggered you're at greater risk of developing other allergies.