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Early Farming Instruments |
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Animals are a major group of multicellular, eukaryotic organisms of the
kingdom Animalia or Metazoa. Their body plan becomes fixed as they
develop, usually early on in their development as embryos, although some
undergo a process of metamorphosis later on in their life. Most animals
are motile - they can move spontaneously and independently. Animals are
heterotrophs - they are dependent on other organisms (e.g. plants) for
sustenance.
Most known animal phyla appeared in the fossil record as marine species
during the Cambrian explosion, about 542 million years ago.
The word "animal" comes from the Latin word animale, neuter of animalis,
and is derived from anima, meaning vital breath or soul. In everyday
colloquial usage, the word usually refers to non-human animals. The
biological definition of the word refers to all members of the Kingdom
Animalia. Therefore, when the word "animal" is used in a biological
context, humans are included.
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