Final answer:
The subject of the question is Biology. The statement suggests that the blank that needs to be filled in is 'ejection fraction'. A low ejection fraction can be an independent predictor of poor prognosis in various heart conditions.
Step-by-step explanation:
The subject of the question is Biology.
The statement '___ is parallel to CHF, is an independent predictor of poor prognosis' suggests that there is a blank that needs to be filled in. Based on the context, the word that should be filled in is 'ejection fraction'.
Ejection fraction refers to the percentage of blood that is pumped out of the heart with each contraction. A low ejection fraction is a sign of poor heart function and can be an independent predictor of poor prognosis in various heart conditions.