Students can practice identifying word parts by filling in the prefix, root word, and suffix for each example.

Let me work through each word carefully to identify the prefix, root word, and suffix.

1. tallest - Already done: prefix (none), root word = tall, suffix = est

2. unhappy - "un" is a prefix meaning not, "happy" is the root word, no suffix

3. preschool - "pre" is a prefix meaning before, "school" is the root word, no suffix

4. disappear - "dis" is a prefix meaning not/opposite, "appear" is the root word, no suffix

5. younger - No prefix, "young" is the root word, "er" is the suffix

6. become - "be" can be considered a prefix, "come" is the root word, no suffix. Actually, let me reconsider. "Become" - "be-" is a prefix meaning to cause to be, and "come" is the root.

7. misspoke - "mis" is a prefix meaning wrongly, "spoke" is the root word, no suffix

8. ungrateful - "un" is a prefix meaning not, "grate" or "grateful"... Let me think. "Grateful" has root "grate" and suffix "ful". So: prefix = un, root = grate, suffix = ful

9. replay - "re" is a prefix meaning again, "play" is the root word, no suffix

10. worthless - No prefix, "worth" is the root word, "less" is the suffix

11. underground - "under" is a prefix meaning below, "ground" is the root word, no suffix

Let me verify each one:
- tallest: root=tall, suffix=est ✓
- unhappy: prefix=un, root=happy ✓
- preschool: prefix=pre, root=school ✓
- disappear: prefix=dis, root=appear ✓
- younger: root=young, suffix=er ✓
- become: prefix=be, root=come ✓
- misspoke: prefix=mis, root=spoke ✓
- ungrateful: prefix=un, root=grate, suffix=ful ✓
- replay: prefix=re, root=play ✓
- worthless: root=worth, suffix=less ✓
- underground: prefix=under, root=ground ✓

Final Answer:

| Word | PREFIX | ROOT WORD | SUFFIX |
|------|--------|-----------|--------|
| tallest | — | tall | est |
| unhappy | un | happy | — |
| preschool | pre | school | — |
| disappear | dis | appear | — |
| younger | — | young | er |
| become | be | come | — |
| misspoke | mis | spoke | — |
| ungrateful | un | grate | ful |
| replay | re | play | — |
| worthless | — | worth | less |
| underground | under | ground | — |