Final answer:
Muscle development, bone formation, and soft hair growth are fetal changes during the second trimester.
Step-by-step explanation:
Fetal Changes during the Second Trimester
During the second trimester of pregnancy, various changes occur in the fetus. Muscles develop and become more coordinated, allowing for movement. The heart stabilizes and functions more efficiently. Bone formation progresses as cartilage is replaced by ossification, forming a stronger skeletal structure. Additionally, during this period, soft hair called lanugo grows on the fetus' body.
However, one of the changes mentioned in the options is NOT a fetal change during the second semester. The correct answer is Heart stabilizes. While the heart does continue to develop and mature throughout pregnancy, it undergoes significant growth and structural changes during the first trimester.
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