Misc: What US state's flag is the only one that features the Union Jack in its design?

Questions

Baby opossums - upon birth when they move to the mother's pouch - are smaller than honeybees. An entire litter can fit in a ----------?

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.?