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I think it is the second answer, sorry if it is wrong/didn’t help.
Answer;
-Gap junctions
Explanation;
-Gap junctions are a specialized intercellular connection between a multitude of animal cell-types. they are organized collections of protein channels in cell membranes that allows ions and small molecules to pass between adjacent cells.
-Gap junctions allow the exchange of ions, second messengers, and small metabolites between adjacent cells and are formed by two unrelated protein families, the pannexins and connexins.
The answer TRUE they do not have a fossil record.
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:
