[DOC] [TLE] embryonic nutrition in birds and mammals (certification) [PAR] (iv) State the formation and role of chorion, amnion, allantois and yolk- sac during 
the ... In these the embryo receives nourishment from the mother through a 
special structure ... Located in the centre of the egg a large sphere of yolk there is 
a small ... in H2O) and also provides a wet environment to the develo- ping 
embryo. [DOC] [TLE] Egg - Wikipedia [PAR] An egg is the organic vessel containing the zygote in which an animal embryo 
develops until it ... Reptile eggs, bird eggs, and monotreme eggs are laid out of 
water, and are surrounded by a protective shell, either flexible or inflexible. ..... 
from the adult body, and by the yolk which the egg provides to nourish the 
embryo. [DOC] [TLE] Chicken Egg Development - EnchantedLearning.com [PAR] Zoom Birds  EnchantedLearning.com. All About Chickens ... There are two 
chalazae anchoring each yolk, on opposite ends of the egg. The Eggshell: The ... 
The yolk contains the food that will nourish the embryo as it grows. The following 
are... [DOC] [TLE] Embryo Development; Stages & Processes of Incubation - AvianWeb [PAR] Air Sac / Allantois Sac: Grows larger as embryo grows. ... It provides the embryo's 
water supply, but also serves as "shock absorber" for the embryo and ... There 
are 2 chalazae anchoring each yolk - one on the top and one on the bottom. ... 
the yolk of eggs and circulates nourishment from the yolk to the developing 
embryo. [DOC] [TLE] Egg (biology) - New World Encyclopedia [PAR] Apr 2, 2008 ... In this way eggs provide a larger benefit, being consumed by many animals and 
by humans. ... Oviparous animals lay eggs in the environment, and the embryos 
.... of the yolk in a yolk sac, which continues to nourish the larvae for a few days 
as ... The eggs of terrestrial vertebrates such as reptiles, birds, and... [DOC] [TLE] Extraembryonic Membranes - Kimball's Biology Pages [PAR] The embryos of reptiles, birds, and mammals produce 4 extraembryonic 
membranes, the ... The amnion protects the embryo in a sac filled with amniotic 
fluid. ... do not make a shelled egg, they do also enclose their embryo in an 
amnion. ... The yolk sac provides a rudimentary connection to the mother's blood 
supply from... [DOC] [TLE] Amniotic Fluid, The Amnion, and the Yolk Sac - Video & Lesson ... [PAR] From a chick developing inside an egg to a human baby growing in its ... 
However, when mammals began using the placenta to nourish their unborn ... 
Just like in birds, the amnion of mammals forms a fluid-filled sac around the 
embryo and... [DOC] [TLE] Chick Embryo Development [PAR] In birds, fertilization occurs about 24 hours before the egg is laid. The newly ... 
forme within the egg, both to protect the embryo and to provide for its nutrition, 
respiration, and excretion. These organs include the yolk sac, amnion, and 
allantois. [DOC] [TLE] Amniote Egg - Biology Encyclopedia - cells, body, human, animal ... [PAR] But thanks to the amniotic egg, reptiles can lay their eggs nearly anywhere on dry 
land. The amniotic egg of reptiles and birds is surrounded by a tough outer shell 
... A third sac, the allantois, stores wastes from the embryo and also fuses with... [DOC] [TLE] chorion | embryology | Britannica.com [PAR] It develops from an outer fold on the surface of the yolk sac. ... In insects the 
chorion is the outer shell of the insect egg. ... oxygen through the porous shell 
from the atmosphere for nourishment of the embryo; it also ... an extra-embryonic 
membrane of reptiles, birds, and mammals arising as a pouch, or sac, from the 
hindgut. [DOC] [TLE] animal development - Reptiles, birds, and mammals | Britannica.com [PAR] In reptiles, egg-laying mammals, and some birds, a pocket-like depression ... and 
there arrange themselves into a sheet of chordamesoderm and of endoderm, the 
... Throughout its development the embryo requires a steady supply of

Question: This sac in a bird's egg is there to provide nourishment to the embryo
Answer: yolk