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.
I believe you meant 'selective breeding'.
Selecitve Breeding is when say a dog breeder, chooses two prospective parents in hopes of achieveing a superior offspring or offspring with desired traits.
Other organisms such as an autotroph
As the population of rabbits goes up, the coyote population rises shortly after. Between 1995 and 2000, the rabbit population began to drop drastically. The coyotes, having no constant food source, began to drop in numbers shortly after.