When the cord precedes the baby down the birth canal, pressure on the cord can cause hypoxia in the fetus. this life-threatening situation is called umbilical cord?

it Is called the "umbilical cord prolapse"

Explanation:in normal birth the baby comes out of the birth canal before the umbilical cord but in some emergency cases such the umbilical cord prolapse the cords slips ahead of the baby and moves into the cervical canal or vagina. This is basically a obstetrical emergency because the cord is at high risk of compression leading to blockage of oxygen and blood to the fetus.

Treatment :

A C section is usually necessary if such an emergency is to occur

if your own plato the answer is b. the fern transitioned from sporophyte generation to gametophyte generation.