At some stage of embryogenesis human embryo looks like vesicle with space. Its wall consists of light small blastomeres and larger dark ones at one pole. What is the name of embryo at this stage?

At some stage of embryogenesis human embryo looks like vesicle with space. Its wall consists of light small blastomeres and larger dark ones at one pole. What is the name of embryo at this stage?

1.  Morula


2.  Zygote


3.  Gastrula


4.  Embryonic disc


5.  *Blastocyst