Hxen.com's tips：Every day persisted can learn English well!-->■Learn English Everyday■
conservation – n. the protection of animals, plants, and natural resources
passionate – adj. having, showing, or expressing strong emotions or beliefs
extinction – n. the state that results when something (such as a plant or animal species) has died out completely
contribution – n. something that is given to help a person, a cause or something else
backyard – n. an area of grass behind someone's house
