In 1864 Nevada entered the United States as _______ thirty-sixth state
Bob Stephenson, a biologist in Alaska who studies the Canadian lynx, a type of wildcat, has learned_______ from studying their tracks in the snow.
_______ lay eggs, but some give birth to live young.
Author Sarah Jewett established her literary reputation with Deephaven, a collection of sketches_______ .
By means of various types of wind tunnels,_______ simulate most of the flight conditions to
which an airplane is subjected.