What feature allows the blood supply to the heart muscle to remain relatively constant regardless of the pressure changes in the coronary arteries due to heartbeats?

Answer:Aterial Anostomoses.

Explanation:

These are formed when two arteries, joined together. (arterio-arterial). it may also formed between vein and veins or between veins and arteries.

They are mostly found in regions of the body where blood supply can easily be damaged or blocked (rectum and anus)

Arterial anastomoses provide dual blood supply to the part of mycardiumn where they are located. Thus they maintain constant blood supply inrespective of fluctuations in presuure.