'This sac in a bird's egg is there to provide nourishment to the embryo'
yolk
INSIDE SCIENCE: This sac in a birds egg is there to provide nourishment to the embryo
This sac in a bird's egg is there to provide nourishment to the embryo
This sac in a bird's egg is there to provide nourishment to the embryo
INSIDE SCIENCE
yolk
INSIDE SCIENCE