a)that life began/centuries ago/scientists think/twenty million/on earth/about
b)endless process/the plants and animals/of evolution/are the products/we see around/us/of an/which
c)by their environment/all the animals/and are molded/are the products of /their habitat.
Please find below the answer to your query.
a)Scientists think that life began on earth about twenty million centuries ago.
b)The plants and animals which see around us are the products of an endless process of evolution.
c)All the animals are the products of the environment and are molded by their habitat.
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