An embryo transitions into a fetus at about week 9 during a pregnancy.
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In the first three months the </span>embryo<span> goes through organogenesis and develops bodily organs, its heart starts beating after the fourth week, brain waves can be monitored after six weeks, and by the eighth week all major body parts are present. After the eight weeks, the embryo becomes a fetus.
(Sorry, I know these aren't the answer choices, but I hope this helps)</span>
Answer:
The most obvious systems that interact with muscular system are the skeletal system, the nervous system and the circulatory system. Muscles are also involved in the digestive system, the respiratory system and the immune system. The circulatory system brings nutrients to the muscles and takes away wastes.
Explanation: explanation is with the answer
