Misc: How many Russians have landed on the moon?

Questions

A rhinoceros has ---------- toes on each foot.?

A robin has nearly 3,000 ----------?

A rodent's teeth never stop growing. They are worn down by the animal's constant gnawing on bark, leaves, and other ----------?

A shrimp has ---------- pairs of legs.?

A shrimp has more than a hundred pairs of chromosomes in each cell nucleus. Man has only ----------?