The superior vena cava is located in the upper chest region and is formed by the joining of the brachiocephalic veins. These veins drain blood from the upper body regions including the head, neck, and chest. It is bordered by heart structures such as the aorta and pulmonary artery.
The superior vena cava (and inferior vena cava) are veins that return deoxygenated blood from circulation in the body and empty it into the right atrium.
Answer:
Viruses are tinier than bacteria. In fact, the largest virus is smaller than the smallest bacterium. All viruses have is a protein coat and a core of genetic material, either RNA or DNA. Unlike bacteria, viruses can't survive without a host.
So life itself is an emergent, complex state, but it is made from the same fundamental, physical building blocks that constitute a virus. Approached from this perspective, viruses, though not fully alive, may be thought of as being more than inert matter: they verge on life.
Explanation:
Sunlight is the source of energy because producers such as grass and trees use photosynthesis to make energy from sunlight. Grass and trees are then eaten by animals like cows, chickens, and pigs. The animal takes in the energy it receives from the foliage, and humans in turn, receive energy from eating the livestock.
1. Burning of fossil fuels.
Under natural conditions the release of carbon from fossil fuels
occurs slowly, as they are sub ducted into the mantle, and CO2 is released
through volcanic activity. However, humans are heavily reliant on fossil fuels,
and extract it from the lithosphere in great quantities. Put in to fire a coal,
oil, natural gas, and other fossil fuels – for industrial movement and power
generation for example, neglect the carbon from the fossil fuels and emits it
as CO2 into the atmosphere.
2.
Land use and land cover change (e.g. deforestation)
Big
part of carbon are stored in living plants. Then, land use changes, most importantly
the clearance of forests (which are very densely inhabited by plants, and
therefore contain a large amount of carbon), can influence the carbon cycle in
two ways. Firstly, removing of vegetation will let the plants die which would
otherwise be capturing carbon from the atmosphere through photosynthesis. And
as dense forests are change by crops/pasture land/built environments, there is
usually a net decrease in the carbon store, as smaller plants (and worse still,
concrete) store far less carbon than large trees. Deforestation also make much
more soil to be eroded, and carbon stored in the soil is rapidly taken into
rivers.
<span>Because the nature is in cycle of the carbon cycle, humans are
affected and cause the lead to a number of amplifications and feedbacks. Thereby
releasing more CO2 to the atmosphere. Increases in global temperature also
affect ocean temperatures, modifying oceanic ecosystems and having the
potential to disrupt the oceanic carbon cycle, limiting the ocean’s capability to
absorb and store carbon.</span>
