In this excerpt from his autobiography, wright’s principal subject is.

Earth's atmosphere is unique among the planets and is able to support life because it contains a large amount of a) oxygen b) helium c) methane d) carbon dioxide

What is another way name for bd? cf, bd, cf, be

Dan runs a busy desktop-publishing company. his company want to increase its exposure, so it runs a new a new promotion each week. the tool dan most likely choses to publicize this is a promotion is a