Afetus has been developing for three months. what will happen next apex

All organs have developed but minor development keep on happening till maturity and delivery

Explanation:

Just after the completion of third week of embryonic development, the essential body organs such as heart, spinal cord (Spine) and brain will begin to form. However, the heart will start functioning properly and thus will pump blood by the end of the week.

Hair will starts developing and also the endocrine system of the baby will start developing with few of the hormones secreting by the end of the week.

Hence, it can be said that vital organ and system will start developing after the first three weeks of the baby

After the completion of three months,  the fetus would have grown upto its full size. All major organs would have formed. But these organs need further development as they cannot sustain the survival of fetus in the outer world. Herination must be complete by this time and the fetus bladder can be seen

 Fetal movements can be seen now. Their gender can also be identified

"a.) well–developed vascular system."