Baby Names Beginning With "D": Meaning: Form of DONAL?

Questions

The highest known score for a single word in competition Scrabble is ---------?

More than 20 percent of men and 10 percent of women say they've forgotten their ----------------- at least once.?

Fleas can accelerate ------------- times faster than the space shuttle.?

Half of all murders are committed with ------------?

The population of the entire world in 5000 B.C., according to the National Population Council, was ---------------?