Answer:
It is because G. stearothermophilus is a thermophile and hence it can sustain at higher temperatures.
Step-by-step explanation:
Geobacillus stearothermophilus is a bacteria that has the ability to survive at a higher range of temperature such as between 30 to 75°C. It exhibits high processivity and a low error rate at temperature higher than even 70 degree Celsius. Such bacterias are known as thermophile
They are usually found in extreme habitats such as deep sea, inside volcanic islands, hydrothermal vent systems etc. Therefore, they can sustained on energy and carbon dioxide from the vents