Answer:
the total mass of organisms in a specific area or volume
Explanation:
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Answer:
wish i could friend, wish i could
Explanation:
sorry, have a good day and life lol
I think the correct answer would be A. The yolk sac becomes the placenta. It is membranous sac that is attached to the embryo. It provides all the nutrition and the blood cells needed by the embryo. It is also called the umbilical vesicle.