Sam Spade in The Maltese Falcon and Rick Blaine in Casablanca ____ of Humphrey Bogart's more famous roles

____,the outermost layer of skin, is about as thick as a sheet of paper over most of the skin.

During the Precambrian period, the Earth's crust formed, and life ____ in the seas.

When fluid accumulates against the eardrum , a second more insidious type of ____

Before the Statue of Liberty arrived in the United States, newspapers invited the public to help determine where ___ placed after its arrival.

A stock _____ at an inflated price is called a watered stock.

Acidic lava flows readily and tends to cover much larger areas, while basic lava ___

Seismic reflection profiling has ____the ocean floor is underlain by a thin layer of nearly transparent sediments.

___and terrifying, coral snakes can grow to 4 feet (1.2 meters) in length.

The leaves of the white mulberry provide food for silkworms,___silk fabrics are woven.

As__in Greek and Roman mythology, harpies were frightful monsters that were half woman and half bird.

Not only___generate energy, but it also produces fuel for other fission reactors.

D.W. Griffith pioneered many of the stylistic features and filmmaking techniques _______ as the Hollywood standard.

___be needed, the water basin would need to be dammed.

Mosquitoes will accepts the malaria parasite at only one stage of the parasite's complex life cycle.

The counterpart of a negative electrons is the positive proton.

Alexander Hamilton's advocacy of a strong national government brought he into bitter conflict with Thomas Jefferson

There are more than eighty-four million specimens in the National Museum of Natural History's collection of biological, geological, archeological, and anthropology treasures.

After George Washington married widow Martha Curtis, the couple comes to reside at Mount Vernon.

Rubberized asphalt can hardly be classified as cutting edge at this stage in their development.

Rhesus monkeys exhibit patterns of shyness similar to that in humans.

In space, with no gravity for muscles to work against, the body becomes weakly.

Fort Jefferson, in the Dry Tortugas off the southern tip of Florida. can be reach only by boat or plane.

Quarter horses were developed in eighteenth-century Virginia to race on courses short of about a quarter of a mile in length.

Supersonic flight is flight that is faster the speed of sound.

Since the dawn of agriculture 9,000 years ago, only a few animal species had been domesticated.

The Betataken House Ruins at Navajo National Monument is among the largest and most elaborate cliff dwellings in the country.

The island of Kauai has much streams, some of which have worn deep canyons into the rock.

It is a common observation that liquids will soak through some materials but not through other.

Surrounded by forested mountain slopes are the town of Telluride, a former gold-mining town 7,500 feet above sea level.

The newsreels of Hearst Metronome News, which formed part of every moviegoer's experience in the era before television, offer an unique record of the events of the 1930s.

Probably the best known of all dinosaurs, the Tyrannosaurus was larger and last of the meat-eating camosaurs.

Unlikely gas sport balloons, hot air balloons do not have nets.

Born in Massachusetts in 1852, Albert Farbanks has begun making banjos in Boston in the late 1870s.

Methane in wetlands comes from soil bacteria that consumes organic plant matter.

Alois Alzheimer made the first observers of the telltale signs of the disease that today bears his name.

Edward McDowell remembers as the composer of such perennial favorites as "To a Wild Rose" and "To a Water Lily."

Animism is the belief that objects and natural phenomena such as rivers, rocks, and wind are live and have feelings.

Newtonian physics accounts from the observation of the orbits of the planets and moons.