The correct answer is Metal.
Sound waves are vibrations which need medium to propagate. Higher the density of medium, the sound travels fastest. Sound travels fastest in solid than liquid and gas. Therefore, in this question sound will travel faster in metal because metal has higher density than air and water and it will not travel in vacuum as sound needs medium to travel.
C. proteins-
The cytoskeleton is what provides structural support for a cell, and the cytoskeleton is made out of fibrous proteins.
Hope that helped!
Answer:
D
Explanation:
The cuticle of a plant helps protect its aerial epidermis from things like environmental stresses and desiccation.