Organisms which can tolerate wide temperature variations are called.................

Explanation

**Step-by-Step Text Solution:**

1. **Understanding Temperature Tolerance**: Organisms can be categorized based on their ability to tolerate temperature variations. Some organisms thrive in a narrow range of temperatures, while others can survive in a much wider range.

2. **Narrow vs. Wide Temperature Range**: Organisms that can only survive within a narrow temperature range are referred to as "stenothermal." In contrast, those that can tolerate a wide range of temperatures are termed "eurythermal."

3. **Prefix Identification**: The prefix "eury-" is used to denote organisms that can tolerate wide variations in temperature. This is derived from the Greek word "eurus," meaning "wide" or "broad."

...