References

(1) https://www.flickr.com/photos/74896762@N00/3166520949/in/photostream/ 

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(2) Tyser RC, Miranda AM, Chen CM, Davidson SM, Srinivas S, Riley PR. Calcium handling precedes cardiac differentiation to initiate the first heartbeat. Elife. 2016 Oct 11;5:e17113.

 

(3) Kumano Y, Tanaka S, Sakamoto R, Kanahashi T, Imai H, Yoneyama A, Yamada S, Takakuwa T. Upper arm posture during human embryonic and fetal development. The Anatomical Record. 2022 Jul;305(7):1682-91. 

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(4) NHS. 9 weeks pregnant guide - Best Start in Life - NHS [Internet]. nhs.uk. 2023 June [cited 2026 Aug 13]. Available from: https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-9/#look-like 

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(5) Guo B, Wang T, Wang Y. Human embryo at 10 weeks’ gestation. American Journal of Obstetrics & Gynecology. 2022 Jun 1;226(6):853-4.