Which system in the body is regulated, in part, by the brain and mobilizes defenses, such as white blood cells, against invading microbes and other disease agents?

It is difficult to assess the effectiveness of complementary and alternative medicines because __________.

A. patients hide the fact that they are using these therapies B. few have been subjected to rigorous scientific study C. there aren't enough people using these therapies to study them D. they are so new, there has not been time to collect data

One reason for the low rate of child vaccinations in the United States is that __________.

A. parents lack access to consistent medical care B. vaccines are ineffective in preventing disease C. parents are not aware that children need vaccinations D. some parents believe vaccines cause autism