I need an introduction of apple and microsoft

2pointswho was mikhail gorbachev? oa. a russian leader who opposed a coupob. a polish leader who founded the labor union "solidarityoc. a soviet leader who called for a closer relationship with the unitedstates, economic reform, and a more open societyd. a soviet leader who called for more oppression in the soviet union

What are the three uses of a screw?

Whats three fourths of 15(this is supposed to be in math but i clicked too fast)