useless trivia: What Word Means: The Russian Name Of Tartu, Estonia?

Questions

More people are killed in Africa by crocodiles than by ----------?

The average adult male ----------, the world's largest living bird, weighs up to 345 pounds.?

More species of ---------- live in a single tributary of the Amazon River than in all the rivers in North America combined.?

Goldfish have four color recepectors in their ---------- compared to our three - the mantis shrimp has ten color receptors.?

The average adult ---------- weighs 21 pounds.?