The answer is They are all organisms made of cells. The cell is the basic unit of a living organism. A cell is a structure that is bound by a membrane and contains organelles and DNA (that contains coded instruction on how the cell should behave). While a bacterium has one cell that functions on its own, a rose and an elephant are higher organisms with numerous cells that function together.
Dark matter is invisible and does not emit electromagnetic radiation. Dark matter is part of a theory that hypothesis the existence of a counterpart to the particles we know in physics, in order to balance the universe that otherwise would be largely unbalanced right now. However, the theory right now is not yet proven.
The answer is 1. This is because electronegativity increases up a group and across a period. So metals are going to be the least electronegative. 4.0 is the most electronegative element on Paulina's Scale!
