Final answer:
B) fluid accumulation causes the increased size of an activated cervical lymph node during infection.
Step-by-step explanation:
The increased size of an activated cervical lymph node during infection is primarily caused by fluid accumulation (B). When the lymph node is activated in response to infection, the lymphatic vessels bring in immune cells, pathogens, and other substances. This influx of fluid, along with the proliferation of immune cells, leads to the swelling or enlargement of the lymph node.
During an infection, lymphocytes within the lymph node undergo division and multiplication (D). This process is part of the immune response to combat the invading pathogens. The increased number of lymphocytes contributes to the overall growth and activity of the lymph node. The fluid accumulation and lymphocyte division together result in the observable enlargement of the lymph node during an immune response.
Understanding the dynamic processes within lymph nodes is crucial in immunology and medicine. The enlargement of lymph nodes serves as a clinical indicator of an ongoing immune response and can be assessed by healthcare professionals to evaluate the body's reaction to infection or other immune challenges. This swelling is a manifestation of the immune system's efforts to contain and eliminate pathogens, providing valuable information for diagnostic and therapeutic purposes.