3. Fill in the blanks with the necessary words in brackets: 1. Ecology is a ... common for all mankind, (problem, question, point, object) 2. All people actively ... in international cooperation on the protection of the natural habitat. (participate, take part, concern) 3. Environmental problems ... their relatively short history, have alreadybeen an object of a number of international discussions, (despite, in spite of, notwithstanding) 4. They have done a great deal of ... to man and they are still doing so for profit and gain, (harm, hurt, damage) 5. They ... about mineral resources, flowing rivers, forests, meadows and fields, (have a talk, speak, say, tell)