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.
In many cases, the exact cause of colon cancer can't be identified. Age is the most significant factor that can increase a person's risk for developing the disease. About 90 percent of people diagnosed with colon cancer are older than 50. Yet, a variety of hereditary and environmental factors also can increase a person's risk. When people get colon cancer in their 30s or 40s, hereditary factors are more likely to be the cause.