Question

Carbon is most abundant in the ___ and ___

Answer 1

The Earth's system is divided in four subsystems: land (lithosphere), water (hydrosphere), air(atmosphere) and living things (biosphere).
Carbon is sixst most common chemical element on Earth. 
The most carbon on Earth is stored in a surprising place: the ocean.This means that the most of carbon is stored in the lithospehere.

Carbon is most abundant in the core and in the atmosphere.

Answer 2

Carbon is most abundant in the atmosphere and core.

In the earth's biosphere hydrogen, nitrogen, oxygen and carbon are the most abundant.

the most abundant gas in the atmosphere is nitrogen followed by oxygen.

Carbon is being added to the atmosphere through burning of fossils like gas, coal, and oil.