What is the main source of energy for the world

Plants that have reproductive structures called cones are?

Guard cells control which event? the growth of plants capture of solar energy gas exchange in leaves water absorption in roots

According the inverse square law, doubling the distance from the source of the sound, a speaker, for example, will drop the sound 6 db each time. if you were standing in the back of an auditorium, 32 feet away from a speaker not using any amplification, would you be able to hear a speaker clearly? why or why not?