Answer:
The simple predicate of the sentence is 'walks'.
Step-by-step explanation:
A sentence is made up of two parts which are subject and predicate. A subject is a place or person or thing about which the sentence is said. The predicate tells about the subject. It consists of the verb and the object in the sentence. the simple predicate is the main word which describes the action done by the subject. In the above sentence, the subject 'the girl in the blue dress' is doing the action of walking. Hence, 'walks' is the simple predicate in the sentence.