A cation is positive.

Body weight is stable when average daily energy intake and output are equal. 

What is the red arrow pointing at?  

Name the hole in the skull.

Name the specific structure pointed to by the black arrow.

This test tube is showing a positive result for salt. What is the test called?

What specific structure is the black arrow pointing to?

Atrial depolarization causes the _________.

When the left ventricle contracts, the __________ valve closes and the __________ valve is pushed open.

Decompensated shock is normally corrected by the body’s homeostatic mechanisms.