30. Which of the following statements about signal transduction is FALSE ? (A) Signal transduction only can start with a signal to a membrane receptor, and ends with a change in cell function. (B) The signal must be amplified in a cascade manner within the cells. (C) Signal transduction can link with all cellular responses respond to external stimuli. (D) Signal transduction closely links with gene expression to alter metabolism. (E) Signal transduction is largely carried out by second messenger molecules.