In this case it is obvious. However, in general a system could be less complex than complexity of its elements. We don't have agreeable way to measure complexity but for now I would argue that complexity of molecule of water (its complete physical and chemical description) is more complex than sum of those molecules in form of a drop of water. Unfortunately so far there's neither accepted approach to measure nor define complexity.
I have always been intrigued that such a complex system like a living cell, could be reduced underlying physics and chemistry. Over time, my reductionistic curiosity was eroded by holistic views that embrace emergence phenomenon as an explanation of complexity. However, eventually, I was disillusioned with the emergence paradigm, as misleading and concluded that the popular interpretation of holism ‘The whole is more than the sum of its parts,’ is profoundly deceptive if used within scientific explanation. My current view is that emergence is a perception ...
Observation of individual neurons doesn't indicate they have intelligence however doe it means that intelligence of a human brain is emergence phenomenon?
Observation of individual atoms and molecules wouldn't revel any gravitation like properties either however we don't call that gravity emergence phenomena. Instead we argue that gravitation like properties of atoms and molecules are not observable. Could you conceder that we may grossly underestimate an "intelligent ability" of individual neurons?