Ilove to use this for my bio hw so my question is a group of similar cells that perform a particular function is a- an organ b- an organ system c- a tissue d- a division of labor

Which best describes the nucleus of an atom a. it is where all of the particle s of the atom are located b. it is the negatively charged part of the atom c. it is where the electrons and the protons are located d. it is the part of the atom with the greatest mass