Classify the following polynomials as monomials, binomials, trinomials.
Which polynomials do not fit in any of these three categories?
`x + y , 1000, x + x^2 + x^3 + x^4 , 7 + y + 5x, 2y - 3y^2, 2y - 3y^2 + 4y^3, 5x -4y + 3xy, 4z - 15z^2, ab + bc +cd + da, pqr, p^2q + pq^2, 2p + 2q`

Explanation

To classify the given polynomials as monomials, binomials, trinomials, or none of these, we will follow these steps:

### Step-by-Step Solution:

1. **Identify the Terms**: Count the number of terms in each polynomial expression.
- A **monomial** has 1 term.
- A **binomial** has 2 terms.
- A **trinomial** has 3 terms.
...