Answer:
This sentence:
While hundreds of new hair and beauty products enter the market every year: sometimes the oldest solutions are still the best.
Is incorrect.
Explanation:
The reasons this sentence is incorrect are two. First of all the colon is used incorrectly. Because it is used to provide specific information that falls into a category that is produced by the sentence before the colons. However, in our case we don't only receive an example of that category's elements. But an explanation. And explanations shouldn't be introduced by colons. They should be followed by them, making it very clear the following elements are part of the category presented. 
 
        
             
        
        
        
Answer:
Well good then, Peter was cheating on her anyway.
Explanation:
I think that this was for the best, never talk to me again Peter!
jk haha  
Have a great summer!! :)
 
        
             
        
        
        
Answer:
The ocean is blue the dolphins are Grey the turtle is green hey I spot a shark why can't you. or The ocean is big the sea is big why can't your heart be to.
Explanation:
its up to you can pick which ever one 
 
        
             
        
        
        
Answer:
Yes, Sylvia has <u>an</u> <em>older</em> brother. 
Explanation:
Double underline the word "an".
Underline the word "older" once.
Put an "I" over the word "an".
I hope this helps you in any shape or form.