What does the term "Affix" include?

The term "affix" specifically refers to morphemes that are added to a base word to alter its meaning or grammatical function. This includes both prefixes, which are added to the beginning of a base word, and suffixes, which are added to the end. For example, in the word "unhappiness," "un-" is a prefix that modifies the meaning of the base word "happy," while "-ness" is a suffix that turns the adjective into a noun.

The other options provided do not accurately describe what an affix is. Base words and blends are related to the construction of words but do not represent the concept of affixes specifically. Vowels and consonants are components of spelling and phonetics, not affixes. Reading strategies deal with approaches to understanding texts and do not pertain to word formation. Hence, the definition of "affix" aligns precisely with prefixes and suffixes, making the first choice the correct one.