Which sentence best defines parallel lines? A. Parallel lines are lines that intersect at 90 degree angles.
B. Parallel lines are lines in the same plane that do not intersect.
C. Parallel lines are lines that are noncoplanar and do not intersect.
D. Parallel lines are lines that occupy the same space and have all their points in common.
E. Parallel lines are lines that intersect to form angles with measures not equal to 90 degrees.

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 a. at what time does the particle reverse direction? b. when is the displacement positive? (round one decimal place and answer in interval notation) c. when is the displacement negative? (round one decimal place and answer in interval notation) d. when is the particle’s acceleration positive? (round one decimal place and answer in interval notation) e. when is the particle’s acceleration negative? (round one decimal place and answer in interval notation)