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.
Quick Answer. The age at which people grow armpit hair varies, but for boys it is often between the ages of nine and 14. Girls typically begin to grow this hair between eight and 13 years of age. Keep Learning.
Photo Credit Jupiterimages/PHOTOS.com>>/Getty Images. Boys and girls start to grow hair in new locations during puberty, which varies drastically from person to person. Girls usually enter puberty between 8 and 13 years of age while boys start puberty between 10 and 15 years of age.