Hyperthermophilic Archaea Possess an Unusual Gyrase Called __________, Which Introduces

Hyperthermophilic archaea possess an unusual gyrase called __________, which introduces positive supercoils into the chromosome in order to protect the DNA from __________.

A) DNA ligase; thermal denaturation
B) DNA helicase; thermal denaturation
C) reverse DNA gyrase; excessive gene expression
D) reverse DNA gyrase; thermal denaturation
E) reverse transcriptase; excessive gene expression