When there is a cut in the skin and bacteria enter the body, the immune system responds. First, macrophages approach the area of the cut. Next, the macrophages surround any bacterial cells and engulf them. What feature of the immune system is best described by this scenario? A. the inflammatory barrier, which is a part of innate immunity B. the phagocytotic barrier, which is a part of innate immunity C. antigen specificity, which is a part of adaptive immunity D. self-recognition, which is a part of adaptive immunity