Passage Summary: We used to measure land by how long it took to plow, but that's useless if you're trying to build apartments. So, once we started using land for things other than farming, we had to switch to measuring by size.

Conclusion: As land uses became more diverse, it became necessary to adopt new measurement standards like acreage.

Reasoning: Old measurement methods based on plowing time were irrelevant for modern needs like determining how many buildings a plot could support.

Analysis: This is an 'Identify the Conclusion' question, so we are looking for the author's main point. The word 'Therefore' in the final sentence is a major signal that the author is wrapping up their argument. The first few sentences provide historical context and a limitation of the old system, which serves as the evidence for the final claim. The conclusion is specifically about the *necessity* of the transition to new measurement units due to changing land use.