A statement about the relationship between variables in a research question is called a(n):

Which two types of terrorism does the Federal Bureau of Investigation define as occurring in the United States?

A) Chemical and biological B) Psychological and economic C) Violent and intimidation D) Domestic and international

Normal exhalation involves all of the following EXCEPT:

A) decreased intrathoracic volume. B) phrenic nerve stimulation. C) relaxation of the diaphragm. D) elastic recoil of lung tissue.