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Reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves. The law of reflection says that for specular reflection the angle at which the wave is incident on the surface equals the angle at which it is reflected. Mirrors exhibit specular reflection. In acoustics, reflection causes echoes and is used in sonar...

In human context, a family (from Latin: familiare) is a group of people affiliated by consanguinity, affinity, or co-residence. In most societies it is the principal institution for the socialization of children. Extended from the human "family unit" by affinity, economy, culture, tradition, honor, and friendship are concepts of family that are metaphorical, or that grow increasingly inclusive extending to nationhood and humanism...

Dance is an art form that generally refers to movement of the body, usually rhythmic and to music, used as a form of expression, social interaction or presented in a spiritual or performance setting. Dance may also be regarded as a form of nonverbal communication between humans, and is also performed by other animals (bee dance, patterns of behaviour such as a mating dance)...

China is seen variously as an ancient civilization extending over a large area in East Asia, a nation and/or a multinational entity. With nearly 4,000 years of continuous history, China is one of the world's oldest civilizations. Prior to the 19th century, it possessed one of the most advanced societies and economies in the world; but through successive dynasties it then missed the Industrial Revolution in Europe and began to decline...

Bodybuilding is a form of body modification, involving intensive muscle hypertrophy. An individual who engages in this activity is referred to as a bodybuilder. In competitive and professional bodybuilding, bodybuilders display their physiques to a panel of judges, who assign points based on their appearance...