Estrogen and progesterone are produced by the _____.

Which one of the following is NOT one of the secondary sex characteristics typical of males:

The penis contains spongy, erectile tissue that fills with _____, causing it to stiffen during sexual arousal.

Beginning at the ninth week of development, the embryo is referred to as a fetus.

Women of childbearing ago go through a cycle about _____ days that make it possible to become pregnant.

The usual PRF ranges from

Gain is a ratio of

Which of these could be the Doppler received  frequency if an operating frequency of 5MHz is used to interrogate blood cells moving towards sound source? 

The _________ directs the voltages from the pulser to the transducer during transmission and directs returning echoes to amplifiers during reception.

Axial resolution affects structures that are