Groundwater response to global changes is a complex function that depends on climate change and variability, topography, aquifer characteristics, vegetation dynamics, and human activities.

UNESCO: Climate Change Effects on Groundwater Resources: A Global Synthesis of Findings and Recommendations | United Nations Educational, Scientific and Cultural Organization

This is yet another extremely complex function, which Social Security describes as leading first to half and then 85 percent of our benefits being subject to taxation.

FORBES: Thomas Jefferson Is Rolling in His Grave -- A Rant on Social Security's Complexity

No: brain function is complex, many different personality types are involved and all such categorisations are bound to be messy.

ECONOMIST: Morality and the brain: Medical diagnosis of malfeasance | The

These technologies will open new doors to explore how the brain records, processes, uses, stores, and retrieves vast quantities of information, and shed light on the complex links between brain function and behavior.

FORBES: President Obama Pledges $100 Million To The Human BRAIN Initiative

The global economy is a complex system and is a function of millions of individual actors making decisions for both rational and irrational reasons.

FORBES: The Bailout Mentality -- The REAL "New Normal"

The surgery is technically complex, and the organ must function even as the child grows rapidly.

WSJ: Scientists Implant Lab-Made Trachea Into Toddler

The old horizon scanning function really has become a much more complex, dynamic, and rewarding activity in the current era.

FORBES: IBM100 'THINK' Draws History Lessons For The Future