Why should we continue to study and learn about ipv4 addressing if the available ipv4 address space is depleted?

IPv4 is the main underlying and the backbone technology that makes it possible for us to connect our devices tot he web/internet.

Explanation:

Whenever a device access the Internet (smartphone, computer, PS4 or other device), it is assigned a unique, numerical IP address. we have currently ran out of IPv4 addresses, but the entire Internet infrastructure currently in place predominantly relies on the IPv4.

IPv6 is currently being integrated into the current structure as new devices are created, but the backbone structure is still IPv4 that is why we should continue to study about IPv4.

answer; receiver;

i think its d if im not mistaken