Definition of opacity for English Language Learners. : 1  the quality of a material that does not allow light to pass through it : the quality of being opaque. : 2  the quality of being difficult to understand or explain.
Research has shown that this is not true, and that brain cells can and do regenerate, especially in the areas related to learning, decision-making, visual recognition, and the way people perceive objects in space.weet. For a long time, scientists thought that it was impossible for brain cells to regenerate because they assumed that any new cells would disrupt the order of the brain.
The liver is a unique organ. It is the only organ in the body that is able to regenerate... that is completely repair the damage. With most organs, such as the heart, the damaged tissue is replaced with scar, like on the skin.The liver, however, is able to replace damaged tissue with new cells.An extreme example is a patient who suffers an overdose from Tylenol. In this example up to 50 - 60 percent of the liver cells may be killed within 3 - 4 days.he liver, however, is able to replace damaged tissue with new cells. An extreme example is a patient who suffers an overdose from Tylenol. In this example up to 50 - 60 percent of the liver cells may be killed within 3 - 4 days.