If a body travels 18 km in 1 hrs, find the average velocity of the body in m/s

We have no idea what the graph shows, or why it may be accurate,  because we can't see the graph.on a different subject, choice ' d ' is the only true statement among the choices.

Iwould think it is temperature, silica, oxides (gases)

Sounds propagates through some kind of medium. usually it's air, but it goes just as well through solid objects like walls, windows etc. a soundwave will compress the (air)molecules in front of it, and if this increased density wave hits your ears, you register it as sound. solid objects like walls are a lot denser than air, this means that they will damp a wave, but also carry it easier.

The inference is supported by evidence in the graph is this is an exothermic reaction where the total release of energy equals a + c.