Answer:
When the doctor has the syringe, it is full of air. So, now after the doctor pushes the plunger, hence the air gets released into the medicine container. After this the doctor then takes the plunger and pull it back. Now , the air gets pulled up back into the syringe, but not only does the air come in but also the medicine because of the pressure build up.
If my answer helped, please mark me as the brainliest!!
Thank You!
