An obstacle that prevents movement or progress in communication is called a(n):
O A. obstructive channel.
OB. useful criticism.
O C. negative opinion.
O D. communication barrier.

Scientists developed the first successful human cell culture in vitro (grown in a lab) in the 1950s by removing cancer cells from a woman. this concept has allowed modern scientists to successfully grow organs. which of the following answers  bestdetermines why there was success?   neurons send a signal to the cell to multiply.a large blood supply to the cell allows enough nutrients for growth.cells are the basic unit of life and thus can regenerate if in a controlled environment.cells cannot reproduce on their own, and the scientist manipulates them to grow.