Darwin observed that the finches on two diffrent island in the galapagos belong to. the same family but showed alot of variations in their break size and shape how can this vaction be justified

The island where not the same and definitely have different foods, terrain, vegetation, etc.

Depending on what on finch eats, it's beak needs to be adapted to that food. And it also depends on what other things it uses for if he needs to poke the ground or rocks in search of food for example. 

Each finch has adapted to its environment.

Hope it helped,

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