Answer:
1.Length is one of the four factors on which the wave frequency depends. So if the length of the string changes then there will be a change in the vibration of string. So in this case if the lengths are different then the wave frequency of both will be different.
2. Wave speed will be the same as it depends on tension and linear density of it.
3. Wavelength itself is find out by the length of string so it depends on length and it will vary with the lengths of strings.
Explanation:
Because the wall reflects sound waves to your ears bouncing off of the walls, even if it's in another room.
Solid metal is all different types of metals or some thing that a magnet can pick up that's a full hard solid
but a non metal is everything not metal that's a solid like plastic a hot glue gun can burn throught plastic and not metal
so in conclusion metal is stronger and thicker than non modal things
The best choice would be letter C hope this helps