L n Canvas Question 21 All of the following are true about natural killer cells except O They can directly bind to antigens. They can destroy virus-infected cells. They can destroy tumor cells. They can destroy cells lacking MHC molecules O They can bind to antibodies that are themselves attached to antigens on cells Question 22 Which of the following statements is false? OMHC molecules differ from person to person OMHC molecules (with peptides) bind to T-cell receptors OT cells have both MHC class I and MHC class Il molecules on their surfaces MHC molecules are on all of our nucleated cells Ocells cannot have both MHC molecules and toll-like receptors on their surfaces at the same time. * Question 23