Freebase(0.00 / 0 votes)Rate this definition: Arbol is a programming language which has been primarily developed for use in Genetic Programming experiments. It is a functional programming language inspired by the ideas of other small and esoteric languages.
Causes. In most cases of colon or rectal cancers, the cause or causes are unknown. Defects in genes that normally protect against cancer play the major role in causing polyp cells to continuously change and become cancerous.
Exposure to pollutants such as metals, dust, chemicals, or pesticides can increase the risk of cancer. At least four types of DNA viruses, hepatitis B and C viruses, Epstein-Barr virus, and human papillomavirus, are directly believed to cause human cancers. Nutrition is emerging as a way to help prevent cancer.