The answer to the 3rd question is that chromosomes are tightly coiled bundles of DNA and carry many genes. For the 4th question, asexual reproduction can occur by binary fission and creates exact genetic copies of a parent.
The big idea to remember is that mitosis is the simple duplication of a cell and all of its parts. It duplicates its DNA and the two new cells (daughter cells) have the same pieces and genetic code. Two identical copies come from one original. Start with one; get two that are the same. You get the idea.
So it is the very last stage!
Answer:
circulatory system is the answer