A predicate is the part of a sentence that contains a verb wich tells something about the subject.
Now, in simple present or present progressive the formula is: subject + verb+ complement; the verb is the predicate. Taking the first three example, the subject is circled and the verb verbs comes after.
Answers are underlined:
The West Indian Manatee <u>is large a sea mammal.</u> 
Manatte <u>rest just below the water's surface.</u> 
Sea grass <u>is one of their favorite things</u> to eat. 
In the last one it can't be eat the predicate because the predicate refers always to the subject, and 'sea grass doesn't eat'. "To eat is a complement"
 
        
             
        
        
        
The victim of a curse, became a lycanthrope so he was locked away in his cellar laboratory so he wouldn't hurt anyone. 
 
        
                    
             
        
        
        
BIG OOOOOOOOOOOOOOOOOOOOOOOOOOOF
 
        
                    
             
        
        
        
Explanation:
The Struggle for Freedom, a narrative of the black experience in America, uses a distinctive biographical approach to guide the story and animate the history. In each chapter, individual African Americans are the pivot points on which historical changes of the era turn.
 
        
             
        
        
        
The little boy was implacable when his parents left him alone with the babysitter.
When the critic reviewed the painting of the rainforest, he could not hep but notice the artist's ardor for the outdoors.
In an effort to assuage angry customers, the store issues everyone a full refund.
Do not become so harried with work, you will forget to enjoy the important things in life like family.
As aloof creatures, most cats prefer to be alone. 
I know that you don't need these any more but here are some that you could use in the future!