Aids is a collection of infections and cancers that occurs because hiv weakens the body’s primary system of defense, exposing other systems in the body to damage. what is this primary system of defense?

a the nervous system
b the circulatory system
c the respiratory system
d the immune system

Which statement supports the principle ideas of jean piaget's philosophy? adults should not interact with teachers. children are best educated through standardized training. adults do not think better than children, but they think differently. children should not form hypotheses until they are certain their findings will be correct.