This tissue forms sex cords which will develop into testes if the bird becomes a male or into the ovary if the bird becomes a female. Several thousand cells near the base of the yolk sac become very ...

The Philippine Eagle Foundation announced its first-ever documented unassisted natural hatching of a Philippine eagle, ...

Their egg cases are sometimes referred to as mermaid's purses, and occasionally as Devil's purses. The egg is a capsule that contains a developing animal and a yolk sac which the young gets its ...

When the baby from Murfreesboro started showing cold symptoms and teething issues in late December, his mom, Jessica Chambers, said she initially didn’t think anything was out of the ordinary. However ...

During human foetal development, erythropoiesis first occurs in the yolk sac, then in the foetal liver and then, in the third trimester and after birth, in the bone marrow. Shortages of donor ...