Morula is a cell stage (AIIMS Nov 2014)
A morula (Latin "morus", mulberry) is an embryo at an early stage of embryonic development, consisting of approximately 12-32 cells (called blastomeres) in a solid ball contained within the zonapellucida.
The morula is produced by embryonic cleavage, the rapid division of the zygote. After reaching the 16-cell stage, the cells of the morula differentiate. The inner blastomeres will become the inner cell mass and the blastomeres on the surface will later flatten to form the trophoblast.