Final answer:
UTF-8 replaced ASCII due to its ability to represent a much wider array of characters suitable for global communication, while also being backward compatible with ASCII.
Step-by-step explanation:
UTF-8 replaced the ASCII character-encoding standard because it offers several advantages, most notably its ability to represent a much wider array of characters from different languages and symbol sets. ASCII is limited to 128 characters, which was sufficient for English but inadequate for global communication. UTF-8, on the other hand, can encode over a million different characters, accommodating not just Latin letters but also diverse scripts such as Cyrillic, Hebrew, Arabic, and many more. Moreover, UTF-8 is backward compatible with ASCII, which means that a UTF-8 file containing only ASCII characters is identical to an ASCII file, ensuring a smooth transition between the two standards.
For example, a user wanting to write text in Chinese, which has thousands of characters, would not be able to do so with ASCII. With the rise of the internet and the need for internationalization, UTF-8 became the standard, as it could handle these requirements while still working well with existing ASCII data.