The phrase "a complex area that" is correct and usable in written English.
You can use it when discussing a topic or field that has multiple layers of difficulty or intricacy.
Example: "The research on climate change is a complex area that requires interdisciplinary collaboration to fully understand its impacts."
Alternatives: "a complicated field that" or "a multifaceted subject that".
This study approach, therefore, provides important implications for palaeohydrographic and palaeoenvironmental reconstructions in a complex area that is characterised by significant geomorphological modifications during the last millennia.
"It is a complex area that needs to be looked at, but it does come back to examiners having a strong culture of ethics to ensure that they do not advantage the pupils that they teach in any way". He added: "It could be looked at - we could come up with a system where a senior examiner who sets the exam for a board is not allowed to teach that board in a school.
This is a complex area that needs further study.
Gender identity development is a complex area that requires considerable expertise to assess and then appropriately advise families.
Race and representation is a complex area that manifests in different form in America from that in the UK, although in both cases it's common to assign peripheral roles to non-white actors.
A relatively complex area that needs further work is how much time needs compensation, and what form of compensation is due for that time.
I'd like to focus the balance of my brief remarks this morning on an additional — and complex — area that is under active consideration both inside and outside the SEC: market structure.
In this area of southwestern Europe, the Pyrenees stand as a major barrier separating central Europe from the Iberian peninsula, one of the major glacial refugia in southern Europe, and also a geologically and ecologically complex area that has suffered itself severe climatic changes, giving rise to a complex phylogeographic pattern that consists of "refugia within refugia" [ 7].
This is an unhelpful oversimplification of a highly complex area that we're only just starting to understand.
Two local examples are the imaginative Tongva Park in Santa Monica and Griffith Park, a larger and more complex area that serves an enormous population and provides a wide variety of gathering places, entertainment venues and areas for outdoor activities.
It is perhaps these most complex areas that will ultimately yield answers on how such cognitive functions arise from in single neurons and neuronal assemblies.
