None two butterflies have exactly the same design on their wings.

Gone With the Wind, the epic novel about life in the South during the Civil War period, took ten years write.

In her time, Isodora Duncan was ............... today a liberated woman.

Industrialisation has been responsible for .................... most radical of the environmental changes caused by humans.

............ that Rachel Carson's 1962 book Silent Spring was one of the chief sources of inspiration for the development of nontoxic pesticides.

In many areas the slope and topography of the land ............... excess rainfall to run off into a natural outlet.

Narcissus bulbs ....................at least three inches apart and covered with about four inches of well-drained soil.

Total color blindness, ....................., is the result of a defect in the retina.

Color and light, taken together, ........ the aesthetic impact of the interior of a building.

A microscope can reveal vastly ..............detail than is visible to the naked eye.