The best research method to investigate cause and effect relationships between variables is .
a.
a. observation.
b.
b. correlation.
c.
c. an experiment.
d.
d. a case study

Aline has a slope of . which ordered pairs could be points on a parallel line? check all that apply. (-8, 8) and (2, 2) (-5, -1) and (0, 2) (-3, 6) and (6, -9) (-2, 1) and (3,-2) (0, 2) and (5,5)