Penguins have webbed feet to help them swim, waterproof feathers and very good vision underwater , they also have thick skin and blubber to help them keep nice and warm so they can have fun and fish for food with out worrying about being very cold. Hope that helped UwU
If you mean what group of elements react the most, the answer is the alkali metals and the halogens because they both only either need to gain or lose one electron. If you mean the most reactive element, it would be fluorine because it has the most electronegativity.
