What percentage of someone’s genetic background may contribute to alcohol dependency?

The percentage of an individual genetic background that may contribute to alcohol dependency is 50%.

Explanation:

Alcohol dependency refers to a chronic disease in which the affected individual has an uncontrollable urge for alcoholic drinks. There are many factors that can cause one to depend on alcohol and one's genetic background is one of them.

Recently, researchers have been able to identify a specific gene that is responsible for development of alcoholic dependency. Before now, scientific studies have been able to proof that children born by alcoholic parents have high tendency of becoming alcoholic adults. The percentage of genetic heritage that is responsible for alcoholic use is as high as 50%

the two answers are a, the population of birds with large beaks will increase on the island, and c, the trait for large beaks will be passed on to future generations through natural selection. the reason for that is because if the birds that have beaks developed for eating small seeds lose all of their food, they will go hungry and eventually starve because they physically cannot eat the large seeds, therefore making the population of large beaked birds higher. also, if the trait of large beaks are dominant on the island over small beaks, then over time the large beaked birds will reproduce more and more, while the smaller beaked birds will reproduce less and less because they can't survive with the food provided. that leads to the trait of small beaks disappearing and the trait of large beaks taking over the island.