Usually when an apple have a worm inside, it has a mark or a little hole in the apple which may indicate that a worm is present inside the apple but some times there is no external sign that refers to the worm inside the apple. Actually the worms are born from very tiny eggs. If such an egg exists within the apple when it is not a completely ripe apple, the worm develops inside it and completely takes the form of the worm.
Now the apple looks perfect from the outside and has a worm inside the apple. Usually there is a mark or some sign sort of thing on the apple which gives us the indication that there might be a worm inside. The question arise here that how the egg of the worm get inside the apple. When apple starts to grow, the eggs of the worm on the leave can enter the apple at that time. Often during the ripping, these worms die out but if they are grown inside the apple, then the situation occur that you have asked for.
Now the apple looks perfect from the outside and has a worm inside the apple. Usually there is a mark or some sign sort of thing on the apple which gives us the indication that there might be a worm inside. The question arise here that how the egg of the worm get inside the apple. When apple starts to grow, the eggs of the worm on the leave can enter the apple at that time. Often during the ripping, these worms die out but if they are grown inside the apple, then the situation occur that you have asked for.