Răspuns :
Substantivul defectiv de plural nu are forma de plural iar cel singular nu are forma de singular.
Defective de plural: lapte
Defective de singular: pantaloni
Defective de plural: lapte
Defective de singular: pantaloni
Sufixele Colective=sunete sau grupari de sunete care se adauga dupa radacina si arata colectivitatea,multimea.