Question

the element known as the combining form
multiple choice
can never begin a word.
is the foundation of the word that provides its meaning.
can only appear once in a term.
is the combination of two roots and a combining vowel.
is the ending of some words.

Explanation:

A combining form is a word - root plus a combining vowel. It can begin a word. The root is the foundation of the word for meaning. A combining form can appear multiple times in a term and is not an ending. It is the combination of a root and a combining vowel.

Answer:

None of the above options are correct. However, if we assume a closest - correct option among these, the foundation of the word that provides its meaning is the root, and a combining form is related to the root with an added vowel. But strictly speaking, the most accurate definition of a combining form is a root + combining vowel, and none of these options fully capture that. If we have to pick from the given ones, the root is the base for meaning and somewhat related to the concept of a combining form, so the closest might be "is the foundation of the word that provides its meaning", but this is still not a perfect definition of a combining form.