Push notifications provide a way for web services to push data to users' devices without waiting for a game to initiate the web request. Push notifications can be sent from any source that can make a web request: a server, a desktop PC, even another Windows Phone.
Medical Definition of Teratogen. Teratogen: Any agent that can disturb the development of an embryo or fetus. Teratogens may cause a birth defect in the child. Or a teratogen may halt the pregnancy outright. The classes of teratogens include radiation, maternal infections, chemicals, and drugs.
Quick Answer. The four most common teratogens are tobacco, alcohol, medications and illegal drugs. Teratogens are substances that could harm a developing fetus by affecting growth and causing birth defects or death. The use of tobacco during pregnancy is dangerous because the smoke causes the blood vessels to constrict.