As of 2010, the two countries that are exceeding 1 billion people are China and India. This are by far the two most populated countries in the world, combined, they make around 1/3 of the world's total population. Even with the law that forbid the Chinese to have more then one child, that lasted few decades, their number still managed to grow (mainly because the law was not so strict in the rural areas). India, on the other hand, has very big fertility rate, there's no laws that restrict the number of children a family can have, and with this rate it's just matter of time when will India take over the number one place, as the world's most populated country.
By mid point equation, x = 2, y = 0.5, the answer is 0.5
You would find it in the disk.
When a country has economic development, the birth rate usually falls. People are working more and wait later in life to have children. While some others now choose to not have any children at all. For a population to be stable, a woman needs to have 2 children, it has fallen over the years in developed countries. This can be problematic for future generations because the newer generations are the ones to support the retiring generations. Labor forces will shrink and this will then hurt the economy.
Hulun Buir Grassland is located in northern China; bordering Mongolia and Russia. Its geological classification is high steppes grassland - grassland plains without any tree. It was formed, along with the surrounding lakes, as part of the Mongolia Highlands by the tectonic collision of India into Asia.