Answer:
The option " The sum has degree of 6 , but the difference has a degree of 7 " is correct.
Step-by-step explanation:
Given that the sum and difference of the polynomials
and 
<h3>Now sum the given polynomials :</h3>




Therefore 
In the simplified <u>sum of the polynomials</u>
we have <u>the degree is 6</u>
<h3>Now difference the polynomials </h3>



Therefore 
In the simplified <u>difference of polynomials</u>
we have <u>the degree is 7</u>
Therefore the option " The sum has degree of 6 , but the difference has a degree of 7 " is correct