Which sentence is grammatically correct?

What type of sentence is: "Because she studied hard, she aced the exam."

Identify the predicate adjective in the sentence: "The movie was exciting."

In the sentence "The book on the shelf is mine," what is the prepositional phrase?

Choose the correct sentence structure:

Identify the adjective clause in the phrase: "The girl who won the race is my sister."

Choose the imperative sentence:

Choose the sentence with correct use of the comma:

What is the compound subject in the sentence: "The cat and the dog are playing in the yard."

What is the correct form of the sentence? "I have less friends than my sister."