If all the power of the variables are greater than or equal to zero, then the expression is a valid polynomial.
So,
1.
are polynomials.
2.
y
2 + s
are all polynomials.
3.
If the degree of the polynomial is 3, then it is a cubic polynomial. If the number of terms of a polynomial is 3, then it is a trinomial.
Hence, is a cubic trinomial.
4.
The highest power is the degree.
Hence, degree of the polynomial is 2 + 4 = 6.