The cardiac cycle is the performance of the human heart from the ending of one heartbeat to the beginning of the next heartbeat.It consists of two periods: one during which the heart muscle relaxes and refills with blood, called diastole, following a period of robust contraction and pumping of blood, dubbed systole.
Answer: four federal agencies
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Answer: How to protect the environment
You can get an underwater mountain range like the Mid-Atlantic Ridge. Normal faults occur at divergent boundaries.
The Grand Canyon is about 5-6 million years old, or was formed about 5-6 million years ago
