Rock has a density of about 3.5 grams per cubic centimeter. are any of the moons composed entirely of rock? if so which ones?
water ice has a density of about 0.9 grams per cubic centimeter. are any of the moons composed entirely of ice? if so which ones?

There is no celestial body known to be entirely composed of one thing. If, you don't count the many different elements embedded in the rock, the only moons that are entirely composed of one thing would be the ones that have no atmosphere or substance on the surface, meaning it would be a barren moon.

May consider a group  g=({0,1},+)g=({0,1},+)where  ++  will work as the xor operator like we work in boolean algebra. note here, that ‘00’ and ‘11’ are not the usual 0 and 1 that we work with everyday. the elements are  called  ‘00’ and ‘11’ and  may not mean  zero (nothing) and one (single). ‘00’ is the identity for the given binary operator +, meaning that any element operated with ‘00’ gets us that element itself.  for a set  ss  in  g′g′  having more elements than just  {0,1}{0,1}  the values for  a+b∈sa+b∈s, such that  a∈s,b∈sa∈s,b∈s, have to be first defined, only then can you determine the value of  1+11+1. the answer could possibly have been  22  if oanswer is25,000