We only use one form of the possessive adjective in Spanish no matter whether we are talking about a singular or plural noun.

False

Explanation:

Possessive adjectives in Spanish have different forms and must be used in the form that agrees in genre, number and degree with the noun to which they are related. Thus, we can say that the possessive adjective changes if we are using a plural or singular noun, in addition to changing whether the noun is masculine or feminine. An example of this are the forms "mi," "mis," "tu," "tus," "su," and "sus."

de estos colores. sounds about right.