SORU: aşağıdaki parçaya göre cevaplayınız
As one can understand from the passage, the causes of immune deficiency ----.
Immune deficiency, which in fact means an
inadequate immune response, may occur for several
reasons. For example, it is a side effect of most
chemotherapy drugs used to treat cancer. Immune
deficiency also occurs naturally. Although the
immune system is not functional at birth, infants are
protected by antibodies they have received from their
mother through the placenta, and infants who
breastfeed also receive antibodies from their
mother's milk. These antibodies offer protection until
the infant's own immune system develops during the
first months of life. In rare cases, the immune system
fails to develop, leaving the child without immune
protection. Exposure to any virus or bacterium can
be fatal to these children. Therefore, they are sealed
into sterile quarters to isolate them from the
microorganisms that are part of the normal world.