Final answer:
An IPv6 address has a size of 128 bits, accommodating a significantly larger number of devices than the previous IPv4 standard, thereby ensuring the scalability of the internet for future growth.
Step-by-step explanation:
The size of an IPv6 address is 128 bits. IPv6 is the most recent version of the Internet Protocol (IP), which provides an identification and location system for computers on networks and routes traffic across the internet. Unlike its predecessor IPv4, which uses a 32-bit address scheme and can support 4.3 billion devices, IPv6 uses a 128-bit address scheme and can support a vastly larger number of devices. The extended address length allows for a huge number of unique IP addresses, ensuring the scalability of the internet as the number of internet-connected devices continues to grow rapidly.