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.
The main cause for the drying up of the lake is drought caused by climate change impacting the inflow to the lake â resulting in a 65% reduction in water levels. Increased diversion for irrigated agriculture, the building of dams and reduced rainfall over the lakeâs surface, are also named as contributing factors.