Which of the following substitutions can help reduce air pollution? using a bike instead of a car
using dumps instead of landfills
using coal instead of oil
using fireplaces instead of a wind farms

Sara goes on a slingshot ride in an amusement park. she is strapped into a spherical ball that has a radius 3*10^2 of centimeters. what is the volume of air in the spherical ball? use this formula: volume of a sphere=4/3pi,r^3 , where r is the sphere’s radius.