Which of the cells below is a phagocytic leukocyte that can engulf a foreign bacterium?

Match each enzyme with the correct macromolecule

Clonal selection is the division of _____ that have been stimulated by binding to an antigen, which results in the production of cloned _____.

What acid is responsible for stomach acidity?

The atrioventricular valves are indicated by which numbers?    

In humans, most nutrient molecules are absorbed by the _____.  

How is the stomach lining protected from the strongly acidic pH of its contents?

What type of epithelium would you expect to find covering a surface subject to physical forces?

From the pulmonary veins, blood flows to the _____.

_____ muscle moves the bones.