Answer: B. pressure changes in the thorax
Explanation:
The veins are the blood vessels which returns the deoxygenated blood from all the tissues and cells of the body back to the heart. The ventricular systole, venous valves, activity of the skeletal muscles and neural control over venoconstriction all influence the movement of the blood in the venous.
The pressure changes in the thorax occurs due to inspiration and expiration. During the process of inspiration, the diaphragm below the lungs contracts and moves downward while the muscles of the ribs pulls downward. When the size of the thoracic cavity increase the air pressure inside the cavity decreases and vice-versa. The pressure inside the thoracic cavity is not related with the movement of the venous blood as it regulates the exchange of the gases not the blood.
Answer:
Providing energy and regulation of blood glucose.
Sparing the use of proteins for energy.
Breakdown of fatty acids and preventing ketosis.
Explanation:
The main function of carbohydrates is to provide energy and regulation of glucose in the blood. It prevent the use of proteins for production of energy and also promote breakdown of fatty acids and preventing ketosis. Ketosis is a process that occurs when our body doesn't have carbohydrates in sufficient quantity for the production of energy. Carbohydrates are the first biomolecules that are used for energy production.
The specific volume will be different for various kinds of cells. The safe answer would be that the new cell will pretty much have the same volume as the one that it divided from. This is true for most eukaryotic cells unless other factors like epigenetics or mutations come into place.
One example of moments a cell would increase in volume is during hypertrophy. This simply means that the cell is increasing in size (compared to: hyperplasia -- which is an increase in number of the cells). Hypertrophy is definitely an increase in volume of the cell but this doesn't necessarily translate to cell division (i.e. just because the cell is big now, doesn't mean it will still be big when it divides).
Another moment of increasing volume of the cell and now also related to cell division would be during the two stages in the cell cycle (i.e., G1 and G2 phases). This is the growth phase of the cell preparing to divide. However when mitosis or division happens, the cells will normally end with the same volume as when it started.
This are safe generalizations referring to the human cells. It would help if a more specific kind of cell was given.
According to the Big Bang theory, the universe was once very dense and is now expanding.
