Answer:
A
Explanation:
Doppler Echocardiogram
A traditional echocardiogram uses sound waves to produce images of the heart. In this procedure, a radiologist uses a transducer to transmit and receive ultrasound waves, which are reflected when they reach the edge of two structures with different densities. The image produced by an echocardiogram shows the edges of heart structures, but it cannot measure the speed of blood flowing through the heart. Doppler techniques must be incorporated to provide this additional information. In a Doppler echocardiogram, sound waves of a certain frequency are transmitted into the heart. The sound waves bounce off blood cells moving through the heart and blood vessels. The movement of these cells, either toward or away from the transmitted waves, results in a frequency shift that can be measured. This helps cardiologists determine the speed and direction of blood flow in the heart.
The energy of the molecules in the ground increases
Answer:
metamorphic
If a rock has shiny surfaces or bands of light and dark layers, then it is blank, which is a metamorphic texture that refers to flat or wavy planar features
B. sexual selection, which alters allele frequencies in the gene pool.