Answer:
1. Head, neck, upper limb, thorax - super vena cava - top of the right atrium.
2. Lower limb - inferior vena cava - bottom of the right atrium.
Explanation:
The Heart pumps the oxygen-rich blood to the different parts of the body to Otake oxygen and nutrients to these organs and then takes the oxygen-poor blood returns from the body to the heart.
The two major vessels that return oxygen-poor blood to the heart are 1. superior vena cava (SVC) that drainages Head, neck, upper limb, thorax and terminate at top of the right atrium, and 2. inferior vena cava (IVC), Lower limb and terminate at bottom of the right atrium.
1. Head, neck, upper limb, thorax - super vena cava - top of the right atrium.
2. Lower limb - inferior vena cava - bottom of the right atrium.
<span>Anton van Leeuwenhoek learned to grind lenses ( 1668) and develop simple microscopes.
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Leeuwenhoek heated the middle of a small soda glass rod , over a flame. On pulling apart the two ends, the glass rod elongated into thin whiskers .
Heating the end of this whisker resulted in a tiny high quality glass sphere. These glass spheres then became the lens of his microscope, with the smallest sphere providing the greatest magnification.
Leeuwenhoek's designs were very basic. The body of the microscope was a single lens mounted in a tiny hole on a brass plate. The specimen was then mounted on a sharp point that sticks up in front of the lens. It's position and focus could be adjusted by turning the two screws.
The entire instrument was about 3 to 4 inches long and had to be held up close to the eye, requiring good lighting and great patience to use.
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.
The spinal cord is the primary means for transmitting messages between the brain and the rest of the body.
