Geometrical Meaning of the Zeroes of a Polynomial

A polynomial of degree 4 can have up to four real zeros.

Yes, a cubic polynomial can have one, two, or three real zeros, depending on how it intersects the x-axis.

If the quadratic polynomial’s discriminant D = b² - 4ac is less than zero, the polynomial has no real roots, so the parabola does not intersect the x-axis.

A polynomial of degree 2 (quadratic polynomial) can have up to two real zeros.