Biology Forums - Study Force

Select the changes in the embryo that indicate that a blastocyst has formed.

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two different groups of cells have formed


cleavage has formed creating a morula


there is a hollow structure, with a mass on the outside and a trophoblast on the inside


many different groups of cells have formed


morula can implant itself into the wall of the uterus and becomes a blastocyst


there is a hollow structure, with a trophoblast on the outside and a inner mass on the inside



You can identify that a gastula has formed because you should note the presence of

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the endoderm


all primary germ layers


the ectoderm


Select all the correct statements.

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In birds, placenta develops from the chorion and extends into the uterine lining.


In humans, placenta develops from the chorion and extends into the uterine lining.


In humans, the placenta (originating from the chorion) allows for the exchange of oxygen and metabolic wastes.


In birds, the placenta (originating from the chorion) allows for the exchange of oxygen and metabolic wastes.


In birds, the chorion is involved in gas exchange


In humans, the chorion is involved in gas exchange


In birds, the chorion combines with the allantois (an extra-embryonic membrane) rather than with the mother’s tissues


In humans, the chorion combines with the allantois (an extra-embryonic membrane) rather than with the mother’s tissues

the mesoderm

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