Thermus and Deinococcus A. survive in extreme environments. B. are both thermophilic. C. are both radiation resistant. D. both serve as the source of Taq polymerase.

Option a, survive in extreme environments

Explanation:

Both Thermus and Deinococcus belong to the group of bacteria that are collectively termed as Deinococcus-Thermus group.

Deinococcus are radiation-resistant vegetative cell as they are able to resist ionising radiation. Also some species of Deinococcus are thermophile.

Thermus are thermophilic bacteria that are able to live in extreme temperature condition and thus are able to tolerate high temperature.

Hence, option A is correct.