The phrase "are the real source" is correct and usable in written English.
It can be used when identifying or emphasizing the true origin or cause of something.
Example: "The researchers concluded that the environmental factors are the real source of the changes observed in the ecosystem."
Alternatives: "are the true origin" or "constitute the actual source."
But what if we ourselves are the real source of violence?
"Ofgem shows excess profits are the real source of soaring energy bills.
This is the idea of the baroque passacaglias: the bass and its harmony are the real source.
But nor does it guarantee changes to entitlement programmes, which do not require annual authorisation and are the real source of long-term spending pressure.
These teams are the real source of power and of decision making at Merrill.
The drainage of aquifers for Israeli industry and agriculture and the lack of serious water conservation efforts in Israel's affluent suburbs are the real sources of the disparity, he said.
And Mr Friedman's sterling reputation may help Los Angeles to attract elite researchers and scouts, who are the real sources of competitive advantage, from other clubs.But far from the $100m a year or so that Mr Morris suggests that Mr Beane deserves, no member of a front office is worth as much as even a half-decent MLB player.
"When it comes to an open internet, Twitter is part of the problem". His argument is that such services are the real sources of content discrimination on the web, because they have the power to exclude certain users at will.
Previous studies reported a high prevalence of this pathogen in faeces of livestock animals [ 19] and in farm effluents [ 20] and this finding could indicate that those are the real sources of surface water contamination.
"That's the real source of their strength," he said.
What does the author suggest might be the "real source" of the appeal of robot battles?
