Ionic bonds result when electrons are tranfered between atoms. Covalent bonds result when valence electrons are shared between atoms. You should be able to identify whether an ionic or covalent bond is being formed between atoms.
The correct answer is A.) Sister chromatids pulled to opposite pole, nucleoli form, cytokinesis.
Plant cells have cell walls, while animal cells don't have cell walls.
I think you are refering to the periodic table. The periodic table is important because it is organized to provide a great deal of information about elements and how they relate to one another in one easy-to-use reference. The table can be used to predict the properties of elements, even those that have not yet been discovered.