Question

multiple choice question
what is the function of the yolk sac?
it produces the amniotic fluid
produces hormones to maintain the endometrium
it suppresses uterine contractions
forms blood cells for the embryo

Explanation:

The yolk sac has several important functions during embryonic development. One of its key roles is in the early formation of blood cells for the embryo. The amniotic fluid is mainly produced by the amnion. Hormones to maintain the endometrium are mainly produced by the corpus luteum and later the placenta. Suppression of uterine contractions is mainly related to progesterone (not directly the yolk sac's main function).

Answer:

Forms blood cells for the embryo