sea snails, clouds water, four japanies

1. Some sea snails produce sulfuric acid, the most potent of
  acids, which they use for dissolving the shells of the
  clams on which they feed.

2. There can be as much as 150-thousand tons of water
  inside a cumulonimbus cloud. That's enough to fill a pond
  a mile long, 300 feet wide and five feet deep.

3. In Japan, the number four is considered to be unlucky
  because the Japanese word for four sounds very similar to
  the word death.