Misc: What is a yarmulka?

Questions

A bird "chews" with its stomach. Since most birds do not have teeth, a bird routinely swallows small pebbles and gravel. These grits become vigorously agitated in the bird's stomach and serve to grind food as it passes through the ----------?

The world's largest mammal, the blue whale, weighs 50 tons at birth. Fully grown, it weighs as much as ---------- tons?

A bird sees everything at once in total focus. Whereas the human eye is globular and must adjust to varying distances, the bird's eye is flat and can take in everything at once in a ----------?

The world's largest rodent is the Capybara. An Amazon water hog that looks like a guinea pig, it can weigh more than ---------- pounds.?

The male ---------- will mate for life, and if the female dies, he remains single for the rest of his life. However, if the male dies, the female will hook up with a new mate.?