Final answer:
A pit in the ear can be indicative of possible kidney issues due to the embryological connection between ears and kidneys; therefore, performing a kidney ultrasound is the correct course of action. During fetal development, hearing begins as the ear structures develop and the auditory nerve forms.
Step-by-step explanation:
If a baby has a pit in the ear and considering the known connection between the development of the ears and the kidneys, the correct action would be to perform a kidney ultrasound. This connection is part of the embryological development where issues in the structure of the ears can indicate potential anomalies in the kidney development. It is also important to note that the physical features of the ears, such as a pit or abnormal shape, can be associated with congenital syndromes that may affect the kidneys. During the development of a fetus, the ears continue to develop and move to their final position, with the outer ears elevating above the surface of the head. The fetus begins to hear as the middle ear and auditory nerve develops, detecting both internal and external sounds. In response to the student's concern, when the fetus can hear effectively, including the mother's heartbeat and potentially music played by the mother, is an important milestone in prenatal development.