That depends on what period you are referring to. In Shakespeare's day they rose from a trap door in the floor of the stage. Much later, a devise called a Corsican Trap, from the play The Corsican Brothers combined a trap door with a huge treadmill that allowed the ghost to rise vertically and float horizontally at the same time.
because they were bored
Not real ghosts, presumably, but stage ghosts. Ghosts appear in the following Shakespearean plays: Hamlet, Julius Caesar, and Richard III. In Hamlet, the stage directions say only "Enter Ghost", which could mean that he entered through the same doors of all the other actors. Indeed in Act 1 Scene 5 he must enter through the same door as Hamlet as Hamlet is following him. The same can be said for Caesar's Ghost and the Ghosts in Richard III. They could also appear on the balcony. Using the trapdoor would have been awkward and ineffective.
trust stage came from london england
There is only one stage in Shakespeare's Globe Theatre in London.
Stage directions appear in italics and/or parentheses/brackets whenever the action is supposed to be carried out. Often, abbreviations such as SL (stage left), SR (stage right), DR (downstage right), UR (upstage right), etc. are used.
because they were bored
Not real ghosts, presumably, but stage ghosts. Ghosts appear in the following Shakespearean plays: Hamlet, Julius Caesar, and Richard III. In Hamlet, the stage directions say only "Enter Ghost", which could mean that he entered through the same doors of all the other actors. Indeed in Act 1 Scene 5 he must enter through the same door as Hamlet as Hamlet is following him. The same can be said for Caesar's Ghost and the Ghosts in Richard III. They could also appear on the balcony. Using the trapdoor would have been awkward and ineffective.
the sperm
Nucleus and nucleolus disappear during pro-phase stage of mitosis,to be specific it disappears in late pro-phase stage and reappers during telophase stage of mitosis.
Because they think if they will not sprinkle salt then ghosts will come on the stage
Very possibly the same actor played the Fool and Cordelia. They do not appear on stage at the same time. When Cordelia returned from France the Fool had to disappear.
The Microtubules of the bipolar spindle assemble and attach sister chromatids to opposite spindle pole, This happens at the Transition into Metaphase.
trust stage came from london england
There is only one stage in Shakespeare's Globe Theatre in London.
Stage Coach
Stage directions appear in italics and/or parentheses/brackets whenever the action is supposed to be carried out. Often, abbreviations such as SL (stage left), SR (stage right), DR (downstage right), UR (upstage right), etc. are used.
so that the mitotic spindel can form and the chromosomes can get attched to the spindel