Vaccination stimulates

A. Interfere with viral replication within cells:Interferons are signaling proteins released by virus-infected cells. They induce neighboring cells to produce antiviral proteins that inhibit viral replication, providing an early defense mechanism against viral infections.

B. Are virus-specific, so that an interferon produced against one virus could not protect cells against another virus:Interferons are not virus-specific. They provide broad antiviral protection by inducing general antiviral states in cells, making them effective against multiple types of viruses.

C. Are routinely used in nasal sprays for the common cold:Interferons are not routinely used as nasal sprays for the common cold due to side effects and limited effectiveness in treating mild viral infections. Their use is primarily therapeutic in serious viral infections or certain cancers.

D. Act by increasing the rate of cell division:Interferons do not stimulate cell division. Instead, they modulate immune responses and activate antiviral defenses, including the production of proteins that inhibit viral replication.

A. Lymph transport is faster than that occurring in veins:Lymph moves much more slowly than blood in veins. Its movement relies on low-pressure mechanisms rather than a central pump like the heart, so this statement is incorrect.

B. Under normal conditions, lymph vessels are very high-pressure conduits:Lymphatic vessels operate under low pressure. They have thin walls and rely on external forces, valves, and vessel contractions to move lymph, not high internal pressure.

C. Lymph transport depends on the movement of adjacent tissues, such as skeletal muscles:Lymph flow is aided by skeletal muscle contractions, respiratory movements, and rhythmic contractions of smooth muscle in the vessel walls. These mechanisms compress lymphatic vessels, helping push lymph toward the thoracic duct and ultimately the bloodstream.

D. Lymph transport is only necessary when illness causes tissue swelling:Lymph circulation is continuous under normal conditions to maintain fluid balance and immune surveillance. Swelling during illness increases demand, but transport is always required.