Answer:
A closed circuit doesn't allow the flow of electrons. an open circuit does. example: if you turn off a switch in your house. you 'broke the circuit it is closed.
Meiosis (SEXUAL cell division) is a type of Mitosis (cell division).
Diploid cell production happens during meiosis when the haploid (n) cells from the parents divide into TWO diploid (2n) cells (which have the complete set of chromosomes from the parents).
Basically, meiosis is required for sexual reproduction (unless in your question you can choose more than one answer...so it'll be meiosis, diploid cell production, mitosis)