Why are organelles surrounded by membranes?

Before the can be observed by using a transmission electron microscope, cells are sliced into very thin sections. what disadvantage does this procedure present in the study of cellular parts

Which of the following statements most accurately describes convergent evolution? the process in which two similar species evolve separately from each other and share similar characteristics the process in which a single species evolves into two or more new species the process in which two entirely different species evolve in response to each other the process in which two different species evolve separately from each other but still share similar characteristics

Are gametes exactly the same? explain why or why not?