PLS HELP FOR THIS PHYSICS TEST

(pls only answer if u rlly know, this is an important test)

Several mountains together form a mountain . a few of these combined form a mountain system. several systems combined form a mountain , which can stretch thousands of miles in length.

Asubject in a clinical research trial experiences a serious, unanticipated adverse drug experience. how should the investigator proceed, with respect to the irb, after the discovery of the adverse event occurrence? a. do not report the adverse drug experience to the irb since it is a common adverse experience. b. report the adverse drug experience to the irb only if there are several other occurrences. c. report the adverse drug experience as part of the continuing review report. d. report the adverse drug experience in a timely manner, in keeping with the irb's policies and procedures, using the forms or the mechanism provided by the irb.

What sort of waves exhibit the doppler effect?