______ fuels were formed from the dead remains of living organisms buried under the earth millions of years ago.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the type of fuels that are formed from the remains of living organisms that have been buried under the earth for millions of years.

2. **Identifying the Key Terms**: The key terms in the question are "fuels," "dead remains," "living organisms," "buried," and "millions of years."

3. **Connecting to the Concept**: The question relates to the concept of fossil fuels. Fossil fuels are a type of energy source that is derived from the decomposition of ancient organic matter.

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