Dr. dawson is conducting a study with military veterans from the vietnam and gulf wars. he plans to evaluate them every year for 10 years to see if those with ptsd have a more pronounced decline in mental abilities and overall memory. this is a(n) study.

a) longitudinal
b) experimental
c) cross-sectional
d) chronological

a) longitudinal

Explanation:

Studies can be observational (when no intervention happens) or experimental (when a variable is manipulated, an experiment is conducted). Observational studies, based on time, are classified as longitudinal or cross-sectional.Longitudinal studies follow the same group of people during a determined period of time.Cross-sectional studies are defined as "snap shots", they compare different groups of people at one specific moment of time.

United states v.  nixon, 418  u.s.  683 (1974),  was  a landmark  united states supreme court case  that resulted in a unanimous  decision  against president richard  nixon, ordering him to deliver tape recordings  and  other subpoenaed materials to a  federal  district  court.