It is caused by the human immunodeficiency virus (HIV), which destroys the body's white blood cells&#151;and thus the body's defense system.
(It; is caused; by the human immunodeficiency virus) (the human immunodeficiency virus; destroys; the body's white blood cells&#151)
It the human immunodeficiency virus
is caused destroys
by the human immunodeficiency virus
the body's white blood cells&#151