2. Living beings are made of
organic and inorganic
substances. According to the
complexity of their molecules
how can each of those
substances be classified?

Gap-fill exercise

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substances, like water,
mineral salts,molecular oxygen and
carbon , are small molecules
made of few atoms. substances,
in general, like glucose, acids and
proteins, are much more complex
molecules made of sequences of
bound in carbon chains. The
capacity of carbon to form chains is one
of the main chemical facts that
permitted the emergence of life on the
planet.