I had to take a screenshot of my response since it was getting flagged for being inappropriate for some reason.
Myocardium, that's because myocardium simply means 'muscular tissue of the heart'. It is not pericardium or connective tissue as these are only small, specific areas of the heart and a heart attack can cause cells to die anywhere in the heart.
Answer: Mutualism
Explanation: The definition of mutualism states " interaction between two or more species where each species has a benefit". The bird is getting food from the insects and the horse is getting the insects removed. Both are benefited.
