Between 3 and 4 weeks, the body plan emerges as the brain, spinal cord, and heart of the embryo are easily identified alongside the yolk sac.
Phakathi kweemveke ezi 3 ne 4, ihlelo lomzimbha liyathoma njengoba ingqondo, ithambo lomgogodla, nehliziyo ye-embryo zibonakala lula eceleni komgodla womthubi (yolk sac).