The relative proportions of adenine, guanine, thymine, and cytosine in species X and Y are not provided; assumptions made include equal proportions of A-T and G-C base pairs; the thermophilic bacterium is most likely species X due to its higher adenine content, suggesting adaptations for stability in a hot environment.
In the absence of specific information on the relative proportions of adenine (A), guanine (G), thymine (T), and cytosine (C) in species X and Y, a common assumption is that DNA typically forms base pairs in a complementary manner, where adenine pairs with thymine and guanine pairs with cytosine. This implies equal proportions of A-T and G-C base pairs in a stable DNA structure. Given that adenine makes up 32% of the total bases in species X and 17% in species Y, it suggests that species X has a higher overall A-T content, while species Y may have a higher G-C content.
Furthermore, the information that one of these species was isolated from a hot spring at 64°C provides additional context. Thermophilic bacteria, adapted to high-temperature environments, often exhibit increased stability in their DNA structures. The higher adenine content in species X aligns with the expected stabilization effect of A-T base pairs, as they form two hydrogen bonds compared to the three formed by G-C pairs. Therefore, based on the assumption of complementary base pairing and the higher adenine content in species X, it is likely that species X is the thermophilic bacterium adapted to the hot spring environment.