Biology

Question

Which of the following occurs during the embryonic stage of

development?

• Chorion appears.

• Nose, eyes, and ears become noticeable.

• Testes descend into the scrotum.

• Heartbeat can be heard.

• Fingernails appear.

Answer

Nose, eyes, and ears become noticeable.

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During the embryonic stage of development, which lasts from fertilization to the end of the eighth week of gestation, the major organs and structures of the body begin to form. At this stage, the nose, eyes, and ears become noticeable as the facial features start to take shape. Other developments during this stage include the formation of the neural tube, which will eventually become the brain and spinal cord, and the development of the heart, which begins to beat and pump blood. However, the other options listed in the question occur during different stages of fetal development.