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.
Allergy - a definition. Allergy occurs when a person's immune system reacts to substances in the environment that are harmless for most people. These substances are known as allergens and are found in house dust mites, pets, pollen, insects, moulds, foods and some medicines. Atopy is the genetic (inherited) tendency to develop allergic diseases. People with atopy are said to be atopic.