Difference between Abstract class and Interface

The following are the difference between abstract class and interface :
1)

A sub class can inherit/extends from only one abstract class i.e. multiple class inheritance is not supported in c# and java

eg:
public abstract class Animal
{
}
public abstract class Vertebrate
{
}
public class Dog : Animal,Vertebrate
{
//invalid
}

A Sub class can implement any number of interfaces i.e. multiple interface inheritance is supported in c# and java

eg:
public interface IAnimal
{
}
public interface IVertebrate
{

}
public class Dog : IAnimal,IVertebrate
{
//valid
}

2)

An abstract class can have both abstract and non abstract(concrete methods)

eg:
public abstract class Animal
{
public abstract void Breath();//valid
public void HasBackbone()//valid
{

}
}

An Interface should have only abstract  methods

eg:
public interface IAnimal
{
void Breath();//valid
void HasBackbone()//invalid
{
}
}

3)
An abstract class contains fields

eg:
public abstract class Animal
{
int i;//ok
}

An interface does not contain fields.

eg:
public interface IAnimal
{
int i;//invalid
}

4)

An abstract class can have constructor

eg:
public abstract class Animal
{
public Animal()
{
//Ok
}
}

An interface can't have constructor

eg :
public interface IAnimal
{
public IAnimal()
{
//Invalid
}
}

5)

Members of abstract can have access modifiers and default access modifiers of data member and member function/method inside an abstract class by default private and class itself has internal access modifier

eg :
abstract class Animal
{
public abstract void CanBreath();//Ok
}

Member function/method of interface cannot have access modifiers and by default all member function/method inside interface are public and interface itself has public access modifier

eg:
interface IAnimal
{
public void CanBreath();//invalid
}

6)
A sub class should not override/implement all methods inside abstract class and only override/implements abstract method

eg:
abstract class Animal
{
public abstract void CanBreath();
public  virtual void HasBackbone()
{

}
}

class Dog : Animal
{
public override void CanBreath()
{

}
}

A sub class should implement all the methods inside interfaces.

eg:
interface IAnimal
{
void CanBreath();
void HasBackbone();

}

class Dog : IAnimal
{
public void CanBreath()
{
}
public void HasBackbone()
{
}
}