WORKSHEET 5

Charles Darwin’s first scientific book, published in 1842, ?????? a since substantiated theory on the origin of coral reefs and atolls.

• to present

• presented

• presenting

• it presents

Different hormones ????? at the same time on a particular target issue.

• usually act

• usually acting

• They usual act

• the usual act

In the late 1880s, Hull House ????? United States’ first welfare state

• to become the

• became the

• becoming one of the

• it became the

Approximately 500 varieties of insectivorous plants, which trap animals for their sustenance, ?????? In the world

• And their existence

• Exist

• They exist

• That exist

Ozone is formed when ultraviolet radiation from the Sun ?????? Molecules into highly reactive oxygen atoms

• Oxygen breaks up

• Oxygen is broken up

• Breaks up oxygen

• To break up oxygen

As a protection device, an octopus ejects black or purple ink to cloud the water when ??????

• Does it escape

• Its escape

• It escapes

• Escapes it

????????, one of the oldest forms of written communication, was used as early as 3000 B.C

• Cuneiform writing

• In cuneiform writing

• Cuneiform writing was

• When cuneiform writing

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

• Viscous

• More viscous

• Is more viscous

• It is more viscous

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

• It is epidermis

• The epidermis

• In the epidermis

• The epidermis is

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

• Reveal that

• Revealed that

• The revelation of

• Revealing about