The ultrasound signal emitted by the external transducer calculates the fetal heart rate by counting the reflected signals that have?

high frequency sound waves

Explanation:

The fetal cardiac activity emits signal that comprises of high frequency sound waves. This signal is received only when it is converted into  a fetal heart rate tracing via computer. These signals are traced through transducers and are shown on the external monitor.

answer; (c); to assure that workers have the right to a safe workplace and that it is the employer's responsibility to provide safe and healthy workplace;

that information cannot be released except with patient permission or to immediate family members. you could state the patient is ok but you cannot give any information on the illness or on treatment being given.