Question

Use the drop-down menus to determine which type of white blood cell is described below. activate memory cells engulf and digest pathogens produce antibodies

Answer 1

I  believe the answer is the B-cell
These are types of lymphocyte derived from the bone marrow and provides the humoral immunity. They produce antibodies; which are proteins that sticks to pathogen preventing them from sticking to cells and flagging them for destruction. The primary role of the B-cells is to make antibodies in large amounts and assist in destroying foreign agents through role as APC. 

Answer 2

T cells: activate memory cells

Phagocytes: engulf and digest pathogens

B lymphocytes: produce antibodies