Which russian leader, who had earned the nickname "the great",announced in 1480 that he would no larger give his allegiance

    which of the following was anecological  result of european exploration from 1400 to 1800?   a.  increased trade with east asia      b.  the spread of epidemic diseases      c.  expansion of english territory      d.  the spread of christianity

Migration the ability to meet current needs without reducing the ability to meet future needs 2. immigration the leaving of one's homeland to settle in a new place 3. migration a situation in which the birth rate is not sufficient to replace the existing population 4. overpopulation the movement of people to a new country 5. sustainable development the increase in the population of a city 6. underpopulation a situation in which resources are being used up at a faster rate than they can be replenished 7. unsustainable development a situation in which the number of people exceeds the available natural resources in an area 8. urbanization the movement of people from one place to another

Pollution levels in beijing are improving in some ways to government programs. what would most improve the sentence