The question above does not indicate the text to which it refers, which makes it impossible for me to provide a specific answer. However, and I will try to help you as best I can.
According to the context of the question, we can state that:
- The question refers to an article on brain research.
- From this, we can infer that the word "trends" means a direction of change or development.
In this case, we can say that the study and research on the development and changes in the composition of the brain slows down research, which takes a long time to complete.
More information:
https://brainly.com/question/15388749?referrer=searchResults
