The basic rhythm of the heart is established by the (1.) pacemaker (2.) valves
(3.) prothrombin (4.) coronary arteries

Pacemaker

Explanation:

establishes the basic rhythm of the heartbeat, it is called the pacemaker of the heart.

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kelp are large brown algae that live in cool, relatively shallow waters close to the shore. they grow in dense groupings much like a forest on land. these underwater towers of kelp provide food and shelter for thousands of fish, invertebrates, and marine mammal species.

e) all of the above