Different classes of immunoglobulin can activate the complem…

Different classes of immunoglobulin can activate the complement system.  However, only one class of antibody can do so using just one antibody molecule, making it the strongest activator of complement.  Which of the following is the strongest activator of complement?

John just bought a house next to Susan. To get to Publix, it…

John just bought a house next to Susan. To get to Publix, it is most convenient for John to pass over a portion of Susan’s property. Susan orally agrees to assign this right over her property (called an easement) to John for a nominal fee. Is this agreement enforceable?