The factors used to determine tumor grade can vary between different types of cancer. Tumor grade is not the same as the stage of a cancer. Cancer stage refers to the size and/or extent (reach) of the original (primary) tumor and whether or not cancer cells have spread in the body. Cancer stage is based on factors such as the location of the primary tumor, tumor size, regional lymph node involvement (the spread of cancer to nearby lymph nodes), and the number of tumors present.
According to an international team of scientists reporting in the Proceedings of the National Academy of Sciences, an asteroid or comet that landed in what is now the Canadian province of Quebec might have led to a significant climate change event known as Younger Dryas.
Basically, dry eyes are caused by a lack of adequate tears. Your tears are a complex blend of fatty oils, water and mucus, which makes the surface of your eyes smooth and clear and protects them from infection. 1. For some people an imbalance in the composition of the tears causes chronic dry eyes.