Introduction to Interfaces

Which of these are correct implementations of the given interface?

interface Animal {
    val numberOfLimbs: Int
    fun move()
    fun communicate()
}

1. fun run() {}
   fun sayMeow() {}
   
   class Cat : Animal {
       override val numberOfLimbs: Int = 4
   
       override fun move() {
           run()
       }
       override fun communicate() {
           sayMeow()
       }
   }
   

2. class Dog : Animal {
       override val numberOfLimbs: Int = 4
   
       override fun move() {
           run()
       }
   }
   

3. fun howl(){}
   
   class Wolf : Animal {
       override fun move() {
           run()
       }
       override fun communicate() {
           howl()
       }
   }
   

4. fun catchPrey(){}
   
   class Bear : Animal {
       override val numberOfLimbs: Int = 4
   
       override fun move() {
           run()
       }
       override fun communicate() {
           howl()
       }
   
       override fun eat()
       {
           catchPrey()
       }
   }
   

5. fun burrow(){}
   
   class Fox : Animal {
       override val numberOfLimbs: Int = 4
   
       override fun move() {
           run()
       }
       override fun communicate() {
           howl()
       }
   
       fun digShelter() {
           burrow()
       }
   }