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The correct answer is absence of jaws.
Lampreys and hagfish are in the class Agnatha, they are jaw-less fish. The members of the agantha class are probably the earliest vertebrates. Scientists have found fossils of agnathan species from the late Cambrian period that occurred 500 million years ago.
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Frozen red blood cells that have been thawed, deglycerolized and reconstituted in an open system must be used within 24 hours.
Cryopreservation of Red blood cells (RBCs) can be done with a long time span of usability of 10 years. Glycerol safeguards RBCs during freezing and defrosting, yet it can cause hemolysis if it is not washed off or eliminated before transfusion. When a unit has been deglycerolized, the shelf life of RBCs in an open system is only 24 hours, bringing about sporadic utilization of Frozen RBCs from the outset of the procedure or in close system cases it is up to 14 days.
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