Looking for late 70s short story anthology, we'd call it YA now. May have included Leiber's "A Pail of Air"

Read this in the school library - all the stories were very dysotopian. One involved a character named 'Emelen' who by the end of the story discovers they are just one of many discarded clones (MLN). Another told the story of a boy and his science fair project involving cereal where he determined that the ruling government (which was a corporation who owned all of the US) was adding a drug to dumb down the populace.