Answer:
The correct answer is C) There is a larger variety of MHC proteins that can be expressed on the cell surfaces of their immune cells, providing a wider opportunity to recognize and attack pathogens.
Explanation:
The crayfish have its nerve cord on the ventral side rather than on the dorsal side. The ventral side is under the Crayfishes' exoskeleton, as opposed to the dorsal side where the exoskeleton is . If it is attacked it will be from the dorsal side and the nerve cord would be snapped easier. The function of the nerve cord is that if it gets attacked by a predator they will go for the top and it will still be able to move.
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Answer:
A double-layered membrane called the pericardium surrounds your heart like a sac. The outer layer of the pericardium surrounds the roots of your heart's major blood vessels and is attached by ligaments to your spinal column, diaphragm, and other parts of your body.
Explanation:
If you have a set of choices my best answer would be traits.