Double-layered sac. the innermost layer of this sac immediately surrounds the heart and is called the pericardium (also called at the base of the heart, this inner layer folds back on itself to become the pericardium. between the layers of this sac is a potential space called the cavity and it is filled with fluid. what is the function of this fluid?

Select all the correct answers. for a claim about the natural world to be considered scientific, what attributes must it have? a).it must be applicable to future events and occurrences. b)it must be based on scientific observations that can be repeated in a controlled setting. c)it must be open to modification if new evidence doesn't completely support it. d)it must be consistent with only a small portion of relevant observations or data.