useless trivia: What Word Means: Toils Incessantly?

Questions

research indicates that mosquitos are attracted to people who have recently eaten----------?

---------- are in the same family as horses, and are thought to have inspired the myth of the unicorn?

rhinos are in the same family as---------- , and are thought to have inspired the myth of the unicorn?

rhinos are in the same family as horses, and are thought to have inspired the myth of the----------?

the average garden variety ---------- has 248 muscles in its head?