A prologue of a book is an example of a message. a.
feedback
b.
channel
c.
source
d.
feedforward

c

Explanation:

the answer to this is source

under a microscope, cancer cells may look very different from normal cells. they often have different sizes and some may be larger than normal while others are smaller. cancer cells are often abnormally shaped and the control centre of the cell (the nucleus) may have an abnormal appearance.

i think? ?

a) the particles of the chair are strongly held together.