The phrase "a primary form of" is a correct and usable part of a sentence in written English.
You can use this phrase to indicate that something is the most important or the main way of achieving a certain goal. For example, "Exercise is a primary form of stress relief for many people."
Even when couples aren't traveling, though, e-mail has become a primary form of communication.
The doctors there found that the patient had a primary form of amyloidosis and that it had spread throughout his body, with the deposits of abnormal protein affecting many of his organs.
This is a primary form of justice which is an integral part of the ethical relation.
That shift has transformed the role of cellphones from optional add-on to a primary form of connecting with others.
The Internet has become a primary form of external or transactive memory, where information is stored collectively outside ourselves.
Importantly within any self-referential construct, unless information is expressly directed and received, it becomes a primary form of biological ambiguity.
Tuberculosis appears mostly in a primary form consisting of a small localized lesion of the lung that either heals completely or remains quiescent for many years.
The central dilemma in the U.S. and U.K. systems is that housing is both a durable good as shelter and an investable asset as a person's primary form of wealth.
Using network-based diffusion analysis, the authors argue that the whales in this group learned the behavior socially from other whales in the group over a period of 27 years in response to a change in the primary form of prey.
A recently-published report by Cycling Scotland (PDF) found that just 1% of Scots use a bike as their primary form of transport.
Parkinson disease is the primary form of parkinsonism, a group of chronic disorders in which there is progressive loss of motor function due to the degeneration of neurons in the area of the brain that controls movement.
