Please find the answers and explanations below: 1. Dendritic cells and Macrophages (The dendritic cells and macrophages are directly involved in physical disruption and engulfment of the foreing antigen/pathogen. These cells contain reservoirs of hydrolytic enzymes which digest the antigen and prevent infection in the body) 2. B lymphocytes and T- lymphocytes (These cells represent the humoral and cell mediated arms of the immune system. These cells are directly involved in interaction with the antigen either by presenting them to antibody producing cells or engulfing and digesting the antigen directly) 3. Dendritic cells and T lymphocyes (These cells are directly involved in physical interaction of the antigen with the cells. These cells contain specific cell surface receptors which are essentially required for recognition and binding of these cells to the antigen and are also involved in presenting these cells to other cells for further action) 4. Macrophages and T-lymphocytes (Helper T cells are physically activated by presence of macrophages and T-lymphocytes which are directly involved in physical interaction of these cells with the antigen and thus processing of the antigen/pathogen by cell-mediated arm of immune system) Solution Please find the answers and explanations below: 1. Dendritic cells and Macrophages (The dendritic cells and macrophages are directly involved in physical disruption and engulfment of the foreing antigen/pathogen. These cells contain reservoirs of hydrolytic enzymes which digest the antigen and prevent infection in the body) 2. B lymphocytes and T- lymphocytes (These cells represent the humoral and cell mediated arms of the immune system. These cells are directly involved in interaction with the antigen either by presenting them to antibody producing cells or engulfing and digesting the antigen directly) 3. Dendritic cells and T lymphocyes (These cells are directly involved in physical interaction of the antigen with the cells. These cells contain specific cell surface receptors which are essentially required for recognition and binding of these cells to the antigen and are also involved in presenting these cells to other cells for further action) 4. Macrophages and T-lymphocytes (Helper T cells are physically activated by presence of macrophages and T-lymphocytes which are directly involved in physical interaction of these cells with the antigen and thus processing of the antigen/pathogen by cell-mediated arm of immune system).