NATURAL processes that cause air pollution, and climate change, within the Earth's atmosphere can consist of: smokestacks and cars
volcanoes and wildfires
power plants and busses
volcanoes and man-made-fires

answer; ///(b) it is composed of four protein chains and four heme groups;

answer >   yes we do, women; have three holes, urethral opening(pee hole, vagina, and the women pee/girls pee out of the urethra like the men do; only they have a single opening to pee/ejaculate.   (sorry if i'm too forward with this, but this is for a biology class, isn't it? )

hope that !         : )