Here are the filled-in blanks for each sentence:

1. Mount Everest is one of the most **impressive** of the 7 world wonders. (impress)
2. Human should conserve biological **diversity** because of its benefit. (diverse)
3. Life in the countryside puts you closer to **nature** and away from the hustle and bustle of the city. (natural)
4. The park aims to help **conserve** otters and other endangered animals. (conservation)
5. Opencast coal mining is among the most environmentally **destructive** activities. (destroy)
6. Too much customer **hesitation** could bring the project to a halt. (hesitate)
7. Paricutin Volcano, a cinder cone volcano in Mexico, last **erupted** in 1952. (eruption)
8. Climbing Mount Everest will be one of your most **wondrous** experiences. (wonder)
9. Rich countries must **urgently** develop a plan to assist countries suffering the ravages of extreme weather. (urgency)
10. Chichester is a **charming** town with plenty to fill a weekend break. (charm)
11. Exploring the Grand Canyon was a dream come true; it felt like a **magnificent** piece of nature's magnificence. (possess)
12. The **charming** beauty of the Great Barrier Reef captivates every visitor who dives into its crystal-clear waters. (charm)
13. Before scaling Mount Everest, climbers must obtain **permission** from the Nepalese government to embark on their journey. (permit)
14. The **explorers** ventured deep into the Amazon Rainforest, uncovering its hidden treasures and mysteries. (explore)
15. Standing in awe of the majestic Niagara Falls, tourists from around the world express their **admiration** for its power and grandeur. (admire)