Also, Doppler can detect abnormal blood flow within the heart, which can indicate a problem with one or more of the heart's four valves. Color Doppler. Color Doppler is an enhanced form of Doppler echocardiography. With color Doppler, different colors are used to designate the direction of blood flow.
(I got armpit hair around 11 1/2 but everyone is different) From around age 13-16 but it can still happen earlier or later (maybe even 12 and 19) got mine just before i turned 14. Brent Lyday.
How Long Does Puberty Last For Boys. When there is an increase in the size of the testicles, it is the first sign of puberty for boys. In the puberty early stage, you can see light hair growth on the genitals and under the arms. A boy starts to gain height and have facial hair during this time period.