Why does adenine always pair with thymine and guanine always pair with cytosine? What two factors determine the base pairing rule?

A. space between nitrogenous bases and opportunity for covalent bonds

B. space between nitrogenous bases and opportunities for hydrogen bonding

C. space between nitrogenous bases and the opportunity for ionic bonding

D. space between ritrogenous bases and the opportunity for metallic bonding

Abody cell has been growing and at synthesis proteins.in the nucleus of this body cell,dna replication is taking place. and a copy of the cells genetic material is copied.which of the following is the best conclusion you can make about the life cycle of this cell ? a) the cell is ready to undergo mitosis.and a chemical signal will send the cell to prophase b)the cell is undergoing meiosis and will cross over the genetic material next c)the cell is in the s phase of interphase and will move next to the g2 phase d) the cell is in the g2 phase of the interphase and is ready to begin diving