1) The strongest natural material known to man is spider silk. It is stronger than steel and more flexible than nylon.

2) The blue whale is the largest animal to have ever existed, with an average length of about 82 feet (25 meters).

3) The sunflower is not a single flower but a cluster of small flowers arranged in a spiral pattern.

4) The fastest recorded serve in tennis was achieved by Sam Groth at 163.7 miles per hour (263.4 kilometers per hour) during a tournament in 2012.