Why do we use the base class type when defining pointers to derived class objects?

Question

The full code of the lesson (Module 7 Quiz of C++) is below:

Dog dogObj;
Cat catObj;
Pet* pet1 = &dogObj;
Pet* pet2 = &catObj;

Why is the following incorrect?

Dog dogObj;
Cat catObj;
Dog* pet1 = &dogObj;
Cat* pet2 = &catObj;

Answer 1

Is that really the full code?
Maybe this lesson can help

https://www.sololearn.com/learn/CPlusPlus/1910/?ref=app