Questions: A small organ found along the course of a lymphatic vessel that filters the lymph and functions as an activation site for B and cells is called a lymph.

The answer is: node.

Explanation:

• A lymph node is a small organ found along the course of a lymphatic vessel.
• It filters the lymph and serves as an activation site for B cells and T cells.
• Lymph nodes play a crucial role in the immune response by trapping foreign particles and facilitating the activation of immune cells.