What is the Significance of Pseudo Header used in UDP/TCP

Question

Why is the Pseudo header prepended to the UDP datagram for the computation of the UDP checksum? What\'s the rational behind this?

Answer 1

"The purpose of using a pseudo-header is to verify that the UDP datagram has reached its correct destination. The key to understanding the pseudo-header lies in realizing that the correct destination consists of a specific machine and a specific protocol port within that machine. The UDP header itself specifies only the protocol port number. Thus, to verify the destination, UDP on the sending machine computes a checksum that covers the destination IP address as well as the UDP datagram. The pseudo-header is not transmitted with the UDP datagram, nor is it included in the length."

E. Comer - Internetworking with TCP/IP 4th edition.