1.Caves are formed by the chemical or action mechanical of water on soluble rock, by volcanic activity, and by earthquake s.





2.Celery, an edible plant is having long stalks topped with feathery leaves, grows best in cool weather.





3.The first fiction writer in the United States to achieve international fame was Washington Irving, who wrote many stories, included � Rip Van Winkle� and  �The Legend of Sleepy Hollow�.





4.Three fundamental aspects of forest conversation are the protection of immature trees, the use of proper harvesting methods, and provide for an  environment that supports reproduction.





5.For each enzyme reaction there is an optimum temperature which maximum efficiency is achieved.





6.Adolescence is a transitional stage in human development from the beginning of puberty to the attainment of the emotion , social, and physical maturity of adulthood .





7.The people native to the northwest coast of North American have long be known for wood carvings of stunning beauty and extraordinary quality.





8.Colonial efforts to manufacture glass at Jamestown---- and later attempts near Philadelphia and Boston---failed despite the abundant of fuel and good raw materials





9.The orbit of a celestial body is usually in the shape of ellipse .





10.Chicago is the third largest publishing center in the United States, exceeding only by New York City and San Francisco.