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.
RNA is an abbreviated form for Ribonucleic Acid. RNA is a nucleic acid that is present in the cells of all living things. Its primary function is to carry genetic instructions from DNA to ribosomes for the synthesis of proteins. There are three different types of RNA, these are messenger RNA, ribosomal RNA and transfer RNA. Ribosomal RNA are transcribed in the nucleus and the are the RNA components of the ribosomes.
<span>since plants are at the bottom of the food web and provide the most energy</span>
D. the squirrel's digestive system breaks down food for energy.