Which I process occurs during the prophase stage of mitosis? Sister chromatids separate at the centromere . Spindle fibers attach to each sister chromatid . The nuclear envelope disappears . The mitosis spindle disappears

Which statements explains what the fossil records indicates? check all that apply. a) earth is 4.5 billion years old b) many organisms have become extinct c) mammals have always existed on earth d) mass extinctions have occurred several times on earth e) the amount of water on earth has decreased over time?