Complex sentence: ROCE is used to prove the value the business gains from its assets and liabilities, a business which owns lots of land but has little profit will have a smaller ROCE to a business which owns little land but makes the same profit.
Split into simpler sentences: ROCE is used to prove the value the business gains from its assets and liabilities. A business which owns lots of land but has little profit will have a smaller ROCE to a business which owns little land but makes the same profit.