Answer:
Scientist count the world humans population with an organization called The United Nations Population Division (UNPD),
Explanation:
Which keeps track of the world population, projects that the world's human population will hit 7 billion on Halloween Day 2011. Admittedly, that is just an estimate: There's no way to know exactly how many people are alive at any given moment, and the true date that humanity's ranks will surpass 7 billion could come in the weeks or months before or after Oct. 31. Nonetheless, the UN's guess is the best there is.
We can maintain the carbon cycle by
According to my research it’s C: Nucleus
Karyotype helps to study the presence and location of genes on chromosome. This also helps to find the mutations such as duplication or deletions.