Final answer:
Cross-presentation is a mechanism used by dendritic cells to present antigens from extracellular pathogens on MHC I molecules.
Step-by-step explanation:
Cross-presentation is a mechanism used by dendritic cells to present antigens from extracellular pathogens on MHC I molecules, rather than MHC II.
During cross-presentation, dendritic cells phagocytose the extracellular pathogen, and the antigen is presented on MHC I molecules to activate CD8+ T cells.
Therefore, the statement 'during Ag-cross presentation, extracellular pathogen Ags loaded to MHC I molecules in MIIC' is true.