The mesosphere is a layer of Earth's atmosphere. The mesosphere is directly above the stratosphere and below the thermosphere. It extends from about 50 to 85 km (31 to 53 miles) above our planet.
An ecoregion<span> is an ecologically and geographically defined area that is smaller than a bioregion. Ecosystem is organisms and their physical environment. </span>
The difference between the fertility rate and the death rate corresponds with the birth rate. When you take the number of children that have been born (alive) in a given year, and then minus the number of the people that have died in the same year, you get the birthrate. It can be positive, when there's more born children than people that died, or negative, when there's more people that died than born children.
A is the answer ps i am also vietnamese
