An ultrasound procedure that evaluates blood flow in an effort to determine the cause of a localized reduction in blood flow is

Doppler sonography is an ultrasound procedure that evaluates blood flow in an effort to determine the cause of localized reduction in circulation. It measures blood flow and pressures in blood vessels. It is a painless way of checking problems with the blood flow.

DNA is antiparallel.

Explanation: DNA is a double stranded helix in which the two strands are antiparallel. Being antiparallel means that as one strand runs from 5'->3' direction, the other strand runs from 3'->5' direction. During DNA each of the two strands serves as a template for a new complementary strand. The synthesis of a new DNA strand is always in the 5'->3' direction, therefore one strand is synthesized continuously in the direction of the replication fork while the other strand is synthesized discontinuously in the direction opposite to the replication fork in short fragments called the Okazaki fragments. The strand that is synthesized continuously is called the leading strand while the strand that is synthesized discontinuously in Okazaki fragments is called the lagging strand.