> For the complete documentation index, see [llms.txt](https://gyansetu-java.gitbook.io/core-java/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gyansetu-java.gitbook.io/core-java/object-oriented-design-principles/is-a-relationship.md).

# IS-A relationship

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To answer this question, refer to the preceding code, and you’ll notice that the interface Hunter is implemented only by class Carnivore. Class Cow doesn’t extend class Carnivore. So, Cow IS-A Hunter is incorrect. Similarly, you can refer to the preceding code to answer all the other options. Option 2 is incorrect because class Tiger doesn’t extend class Herbivore. Option 3 is correct because the interface Movable is implemented by class Animal, which is the base class of Herbivore, extended by class Cow. Option 4 is incorrect because you can’t traverse the hierarchy tree down to determine an IS-A relationship. Evaluate it like this: An Herbivore IS-A type of Animal with some additions or modifications because an Herbivore can modify (override) methods of class Animal and add new ones. But Animal IS-NOT-A Herbivore. Animal can also be a Carnivore.

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If you can traverse up, from a derived class or interface to a base class or interface, following the connecting arrows (lined or dashed), the derived entity shares an IS-A relationship with the base entity.

#### Problem :

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