### I have trouble with remembering sets. So these are my questions, and can someone show me how to do them?

(1)Z is the set of all letters of the alphabet. Z={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z} (a) A is a subset of set Z. A= {a, b, c, d, e,