Answer:
Option (4).
Explanation:
Signal transduction may be defined as the process by which the physical or chemical signal can be transmitted in the body by the series of the different molecular events. Proteins kinases are important for the signal transduction pathway.
The signal transduction pathway occurs in the early as well as in the modern life. Molecular techniques has provided the evidence that cell signalling process is quite similar in the common ancestors and modern organism. Some biochemical molecules are similar that takes part in the signal transduction pathway.
Thus, the correct answer is option (4).