Which makes viral infections difficult to defeat

(a) the immune system must attack the body’s own cells

(b) macrophages work slowly

(c) viruses live outside of cells

(d) viruses are attacked by a nonspecific immune response

Is it considered muscle s ennervation if sympathetic fibers innervate the vessels within the muscle?

Describe the response the kidneys have to dehydration and excessive water intake. what happens to the concentration of urine in each case ?

Which description shows competition in an environment? an organism that feeds on some food an organism that finds a place to sleep three organisms of the same species living in an area three organisms battling over limited resources