In his research paper about the density of nutrients in farm milk, Jamal wrote: "Over the last two decades farm milk has become more nutrient-dense."
To improve this sentence, Jamal could write: "Over the last two decades, the nutrient density of farm milk has increased."
1. By specifying "the nutrient density of farm milk" instead of just "farm milk," Jamal's sentence becomes more precise and focused on the nutrients specifically.
2. Including "has increased" instead of "has become" provides a clearer indication of the change in the nutrient density of farm milk over time.
3. The addition of a comma after "decades" helps to separate the introductory phrase, making the sentence more grammatically correct and easier to read.