Answer:
Red blood cells
Explanation:
Hemoglobin carries oxygen in red blood cells
<em><u>Nitrogen</u></em><em><u> </u></em><em><u>is</u></em><em><u> </u></em><em><u>not</u></em><em><u> </u></em><em><u>a</u></em><em><u> </u></em><em><u>product</u></em><em><u> </u></em><em><u>of</u></em><em><u> </u></em><em><u>photosynthesis</u></em>
You can carry out a test ,
1- take a sample of the air in a test tube
2-add limewater to the test tube
3- result : if it turns milky/cloudy it has microorganisms
4- reason: because every microorganism respires , and so it produces Carbon dioxide .
and limewater is the test to show the presence of Carbon dioxide .
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.
