Use the pull-down menus to insert the best terms that make t…

Use the pull-down menus to insert the best terms that make these sentences true: In DNA, nucleotides containing the base cytosine always base pair with nucleotides containing the base .  Similarly, DNA nucleotides containing the base thymine always base pair with nucleotides containing the base .  The only exception to these rules exists when we focus on RNA molecules, where thymine nucleotides are replaced by nucleotides containing the base .