Increased in pitch (frequency). It's the doppler effect.
if we wipe out an animals natural habitat, or introduce new wildlife the animals could die. This could cause a major problem in the areas ecosystem. That is what i know, and i think that major problems would happen, like to many of one species, which takes all the food from the other species, causing major problems, and even more animals to die.
Eco- friendly means earth friendly or not harmful to environment
