How does blood get back to the heart from the legs?

The Bundle of His is:

A monocyte:

Of the following events involved in hemostasis, which occurs first?

Which of the following is NOT  true regarding hemostasis:  

If the SA node is not functioning, an ECG will show ________.  

Which layer would contain relatively large amounts of iron (Fe)?

Which substance can diffuse directly through the cell membrane of the capillary endothelium?

Using the diagram above – match wave to its most accurate description

  Using the diagram above – match wave to its most accurate description