Lipids in the diet can be .

The ion with the lowest blood level is .

Clusters of neurons in the medulla oblongata that regulate blood pressure are known collectively as .

Which primary germ layer gave rise to the cells that eventually became the central nervous system?

They must be able to interact with their target tissue in a specific manner in order to activate a coordinated set of events.  

Renin is released in response to .

Which of the formed elements arise from myeloid stem cells?

 Which type of immune response is most directly effective against bacteria?

 What is the function of the conchae in the nasal cavity?

During what process does the amnion envelop the embryo?