All of the following are examples of innate (nonspecific) defenses EXCEPT

At age 7, Juan was exposed to the chicken pox virus and was ill for 2 weeks.  At age 17, he was again exposed to the virus, but this time he did not become ill.  Which defensive cells were responsible for sustaining his long-lasting immunity to this virus?

Atrioventricular valves are closed by 

The following structure is part of the upper respiratory tract

Which of these are involved first in stopping blood flow from an injured blood vessel?

How does the digestion and absorption of fat differ from that of carbohydrates?

Nutrients absorbed into the bloodstream travel first to the ________ before arriving in the inferior vena cava.

The abdominal cavity is lined with a membrane called

Chewing and churning food in the GI tract is an example of ___________________.

Macrophages are __________ that move from the bloodstream to tissues.