The answer is C “volcanic activity was more common in the past than it is today
i hope this helps you
from google:
"The Earth gets hotter as one travels towards the core, known as the geothermal gradient. Geothermal gradient is the amount the Earth's temperature increases with depth, indicating heat flowing from the Earth's warm interior to its surface. On average, the temperature increases by about 25°C for every kilometer of depth"
A rational number can be in the form of a fraction, integer, whole number..
In this case, the square root of 36 is 6. For the other answer choices, you'll get an irrational number.
Therefore, the answer is square root of 36.
