To identify the word whose main stressed syllable is placed differently from that of the others, let's analyze the options in each question.

1. **1A. backyard** (stress on 2nd syllable)
**1B. remote** (stress on 2nd syllable)
**1C. Korean** (stress on 2nd syllable)
**1D. wonder** (stress on 1st syllable)
**1E. temple** (stress on 1st syllable)
**1F. waterfall** (stress on 1st syllable)
**Answer: D and E have different stress**

2. **2A. degree** (stress on 2nd syllable)
**2B. forest** (stress on 1st syllable)
**2C. plaster** (stress on 1st syllable)
**2D. station** (stress on 1st syllable)
**2E. essential** (stress on 2nd syllable)
**Answer: B, C, D have different stress**

3. **3A. zodiac** (stress on 1st syllable)
**3B. essential** (stress on 2nd syllable)
**3C. historic** (stress on 2nd syllable)
**3D. travel** (stress on 1st syllable)
**3E. quiet** (stress on 1st syllable)
**Answer: A, B, C have different stress**

4. **4A. organize** (stress on 2nd syllable)
**4B. windsurfing** (stress on 1st syllable)
**4C. travel** (stress on 1st syllable)
**4D. idyllic** (stress on 2nd syllable)
**4E. historic** (stress on 2nd syllable)
**Answer: B has different stress**

By analyzing each group, try this:

- 1: D and E
- 2: B, C, D
- 3: A, B, C
- 4: B

**Final Answer: D. wonder**