Which of these is not a requirement or influence on chemical cycling of inorganic nutrients in a natural ecosystem?
a. a reservoir for the elements in the earth
b. the biotic community and its food chains
c. human activities
d. the input of geothermal energy
e. an exchange pool from which producers draw their nutrients

The correct answer is option d.

Explanation:

Chemical cycling illustrates the systems of concurrent circulation of elements between other states, compounds, and substances, and then return to their original state, which takes place in space, and on many objects in space comprising the Earth.  

Chemical cycling of the nutrients (inorganic) is needed to maintain the conservation of nutrients on Earth. The chemical cycling of nutrients in a natural system requires a pool for the elements, the activities done by human beings, the biotic community and its food chains, and an exchange pool from which producers extract their nutrients. All the mentioned factors are associated with affecting a chemical cycling in exception to the input of geothermal energy.  

≅200-130 milions years ago pangea splited in 2 continents