I need help figuring this out. Thank you!

Ineed the definitions of all of these words nasap i will give 1o points to whoever awnsers

What are tissues? a groups of tissues that work together b basic units of structure and function c groups of cells that perform the same function d multiple organs that perform a major function

Which is an advantage of having memory cells when a pathogen is encountered for a second time. a) the memory cells are what proliferate into clones of cells in response to the binding of an antigen. b) memory cells are vital to the primary immune response in that they immediately recognize pathogens even at the first encounter. c) memory cells are essentially effector cells that are short lived and attack antigens even without having a receptor specific to that antigen. d) it ensures that more lymphocytes with a receptor specific to a particular antigen will be present than in a host that had never encountered that pathogen.