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Fossils are the traces of animals or plants which
have ___1___ left on rocks
or ice. These traces may have been preserved ___2___
millions of years. There are several different types of fossils. In
some ___3___, the actual
remains of the organism are found to be preserved.
How is ___4___ a fossil
formed? When an animal ___5___, its body would
naturally decompose.
However, certain ___6___ of the animal's body, such as
its bones or shell, take a
long ___7___ to decompose.
___8___ this animal is quickly
buried ___9___ soil or rock, its bones or shell would stand a
good ___10___ of being 'unspoilt' or preserved. A good
___11___ of an
animal that is preserved
this ___12___ is the mammoth, a huge furry animal
___13___
resembles an
elephant. Under the ice in Siberia and Alaska, whole
mammoths are ___14___ to be preserved.
In most cases, however, we do not find the actual
remains of the plant ___15___ animal. This is because
these remains have ___16___ disintegrated.
In ___17___ cases, the fossils found may just
___18___ the
cast or mould
of the bodies of animals; just like how a piece of
jelly would ___19___ the shape of the mould it is
contained ___20___.
The study of fossils is important because it is
___21___
this study that we
know what types of plants and animals existed on
___22___ long ago. Fossils are
also able to ___23___
us about how life evolved. For example, with the
study of fossils, we ___24___
that the elephant is descended ___25___
a creature the size of a pig! |
