All of the above. They all right
Well it occurs in igneous, metamorphic, and sedimentary rocks.
quartz is a mineral, not a rock.
it is abundant or in other words rich.
Explanation:
Echoes occur due to the reflection of sound from any obstacle, but not all the reflected sound waves lead to the phenomenon of echo. For the echo to be heard it actually depends upon the human perception as well, human ears can encounter the difference between the sound wave directly form the source and the reflected sound waves only if there is a minimum time gap of one-tenth of a second. For this time gap in the atmosphere at normal temperature and pressure the obstacle must be at least 7 meters away from the sound source.
Answer:
Light waves slow down as they travel from gas to solid.
Explanation:
The speed of light is often quoted with reference to a vacuum. Light travels fastest in a vacuum and in a gas.
When light travels through other media such as solids or liquids, the speed of light is decreased due to absorption and scattering of photons by molecules as well as remissions.
Hence the speed of light decreases from gas to solid.