MHC class I molecules present peptide fragments that are either “self” or “nonself”; in either case, the fragment becomes bound to the molecule while

Exudate formation delivers substances to eliminate injurious agents, and the resulting increase in interstitial hydrostatic pressure leads to increased fluid uptake by lymphatic capillaries.

Poison ivy contains a toxin that acts as a hapten by

Helper T-lymphocyte activation involves MHC class I, whereas cytotoxic T-lymphocyte activation involves MHC class II.

 24. This intaglio printing process involves carefully and cleanly scoring a metal plate.

The pericardium helps prevent overfilling of the heart and it lessens the friction of movements during heartbeats.

23. This intaglio process employs acid to mar the surface of a metal plate. 

The carotid bodies contain _________ chemoreceptors that respond to changes in ________________.

The opening and closing of the heart valves is caused by

Interleukin 1 and interferons act as