Final answer:
Plasma cells are the connective tissue cell that is derived from B lymphocytes. They can secrete soluble antibodies.
Step-by-step explanation:
Plasma cells are the connective tissue cell that is derived from B lymphocytes. Plasma cells are a type of B cell that has differentiated in response to antigen binding, and they have the ability to secrete soluble antibodies. These cells contain a large amount of cytoplasm packed with the protein-synthesizing machinery known as rough endoplasmic reticulum.