As doctors warn it can cause a dangerous reaction with a host of common drugs... 1  Researchers warn that grapefruit reacts with many medicines. 2  The fruit can cause devastating side-effects from stomach bleeding to kidney problems. 3  Doctors say the public is ignorant to the dangers and putting themselves needlessly at risk.
According to the definition of the question (based on light reflection and not light emission), a well-polished mirror is the the whitest substance on earth. The main reflection layer is usually made out of silver.
The answer here too is: Yes! The best example of this is carbon. We all know that carbon is one of the most important elements in our planet; all living things contain carbon. Pure carbon is known to us as diamond, if arranged one way in three dimensions; and graphite if arranged in another.