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.
Forest Fire
A forest fire is an uncontrolled
fire occurring in nature. Wildfire smoke is composed primarily of carbon
dioxide and water vapor. Small particulates suspended in air which come in solid
form or in liquid droplets are also present in smoke. Other common smoke
components present in lower concentrations are carbon monoxide, formaldehyde,
acrolein, polyaromatic hydrocarbons, and benzene. 80 -90% of wildfire smoke, by
mass, is within the fine particle size class of 2.5 micrometers in diameter or
smaller. The vertical lift of a severe thunderstorm can be enhanced in the area
of a large wildfire, which can propel smoke, soot, and other particulate matter
as high as the lower stratosphere.
The answer is... The organisms and the abiotic factors:)
There might be no food or places to live!