I believe that the answer would be D, both the speaker and the microphone
By integrating two or even more materials whose properties are quite distinctive is composite materials. The different materials work together to build special properties for the composite, but within the composite one can easily tell the various materials apart that they don't dissolve or mix together.
It is also recognized as Fiber-Reinforced Polymer (FRP) composites, which are constructed from a polymer matrix strengthened with engineered, man-made or natural fiber like glass, steel or aramid or other strengthening material.
- Their high dimensional consistency helps them to preserve their shape, be it hot or cold, wet or dry.
- This renders them a common material for outdoor frameworks such as wind turbine blades.
- These have less resistance to cracking than metals but more durability than most polymers.
Hope it helps for you : )
The smallest functional and structural unit of an organism, usually microscopic and consisting of cytoplasm and a nucleus in a membrane.
