Here's why:
* Root: The core meaning of a word. For example, "graph" means "write."
* Suffix: A word part added to the end of a root word to change its meaning or grammatical function. For example, "-ing" in "writing" changes the word to a verb.
* Prefix: A word part added to the beginning of a root word to change its meaning. For example, "pre-" in "prewrite" indicates something done beforehand.
Affixes are the collective term for both prefixes and suffixes, they are word parts that are attached to root words to alter their meaning.