Thin layers of <span>calcium carbonate
Glad to help :)</span>
D.India experienced political unrest for many years
Pennsylvania and Illinois are states in the United States that have the greatest quantities of <span>trichloroethylene (TCE). TCE is a toxic contaminant that can be found in drinking water. It is a blue liquid with an odor similar to chloroform. TCE consumption is harmful because it can lead to liver damage, kidney damage and cancer. TCE is also found in air and soil and is considered an environmental contaminant. </span>
Learning theorists call the presentation of a stimulus that increases or maintains a response as positive reinforcement. It contains the addition of reinforcing stimulus after a behavior that makes it more likely that the behavior will occur again in the future. When a satisfactory outcome, event or reward occurs after an action, that particular answer or behavior will be strengthened such as a child receiving a gold star for doing a core.