Paragraf Test-10 Soru=9

Bacteria ……………

The story of the biological relationship between man
and micro-organisms is one of evolution. Although
there is fossilized evidence of the existence of bacteria
thousands of years ago, we know that mutation of
strains of bacteria has occurred and altered their
properties. Even in the last hundred years the
bacterium which made scarlet fever a deadly disease
in the 19th century has ceased to be an organism of
high strength. However, nowadays' the viruses are
much more active and of far greater significance than
formerly, as the widespread use of antibiotics has
resulted in some strains of organisms developing a
resistance to the antibiotics.