________ are materials which are not malleable and ductile and breaks easily.a.Opaqueb.Ductilec.Elasticd.Brittle

The term that fits the description of materials that are not malleable and ductile and break easily is d. Brittle.

Explanation

Brittle materials are characterized by their tendency to fracture or break rather than deform when subjected to stress. This contrasts with ductile materials, which can undergo significant plastic deformation before failure. For example, materials like glass and ceramics are typical examples of brittle substances as they can shatter upon impact rather than bending or stretching. Malleability relates to a material's ability to deform under compressive stress, like metals that can be hammered into thin sheets. In contrast, brittle materials lack this property, making them less adaptable to stress without breaking. Understanding these properties is crucial in material science and engineering applications where the choice of materials under different conditions is essential for structural integrity and durability.