During mitosis the four centrioles appear visibly and move to the ends of the nucleus one pair at each end<span> then they produce a series of threads that attach to the chromosomes During cell division the threads split the chromosomes and drew them towards the centrioles</span>
It shows the evolution of certain species through the bone structures of the fossils.
Transport
The protein is working to transport substances across the membrane.
Using little tweezers you can pull each strand