Answer:
Larger arteries that are better able carry blood throughout the body
The biome in which polar bears are found is very cold.
Explanation:
How Age and Exercise Affect Your Max Heart Rate. The relationship between the heart and exercise has been studied for more than six decades and the research is clear: Max heart rate—the highest heart rate you can safely hit during exercise—decreases with age regardless of lifestyle or level of fitness.
Specific events or chronic pressures.
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