Image result for Is work done when you carry a book across the room at a constant velocity
Work is not done when you carry an object forward. You may have learnt that carrying an object and moving horizontally at a constant velocity has no work done. The truth is, there is a slight amount of work done due to overcoming air resistance in the horizontal direction.
The two differences you see when comparing the four chambers of the heart is that the arteries have a thicker wall and veins have thin walls and that the arteries carry oxygenated blood away from the heart which means they get more pressure than veins.
The atmosphere transfers heat energy and moisture across the Earth. Incoming solar radiation (insolation) is redistributed from areas in which there is a surplus of heat (the equator) to areas where there is a heat deficit (the North and South Pole). This is achieved through a series of atmospheric cells: the Hadley cell, the Ferrel cell and the Polar cell (Figure 2). These operate in a similar way to, and indeed interact with, the ocean conveyor.
For example, as the oceans at low latitudes are heated, water evaporates and is transported poleward as water vapour. This warm air eventually cools and subsides. Changes in temperature and CO2 concentrations can lead to: changes in the size of atmospheric cells (in particular, the Hadley cell is susceptible to these alterations); warming in the troposphere; and disproportionately strong warming in Arctic regions. The strong interactions between ocean and atmospheric dynamics, and the significant feedback mechanisms between them, mean that climate researchers must consider these Earth components as interlinked systems. The necessity to assess ocean-atmospheric changes at the global scale has implications for the way in which research is conducted. It is only by integrating palaeo evidence of past changes, with present day monitoring, and projected models,
