"Acquisition of knowledge," he says early in the book, "is a principal function of the brain".
Participation in national government is a principal function of the regions: regional councils may initiate parliamentary legislation, propose referenda, and appoint three delegates to assist in presidential elections, except for the Valle d'Aosta region, which has only one delegate.
According to its Constitution, a principal function of WHO "is to act as the directing and coordinating authority on international health work", in support of which it "may make suitable arrangements for consultation and cooperation with NGOs in carrying out its international health work" [4].
From some of these early cnidarians through to insects and molluscs, a principal function of NO is to regulate olfaction and feeding and their related learning behaviours (see reviews by Davies, 2000; Moroz, 2001; Trimmer et al., 2004; Palumbo, 2005).
A principal function of the pharynx is to ingest food, to mechanically process it, and to deposit it into the intestine.
A principal function of the Kinect sensor is to compute the depth (i.e., the distance from a sensor) as a laser scanner does.
Part of the effort to automate war, to entrust the choice of targets to machines, a principal function of the system would be to remotely pilot drones all over the world, ultimately reaching the North Pole.
Among these, IGF1 induction of PI3K/AKT pathway is a principal regulator of osteoblast functions (Fujita et al. 2004; Levine et al. 2006; Raucci et al. 2008; Liu et al. 2007).
In any event, the amount and nature of solar energy entering inland waters is a principal determinant of the structure and function of the ecosystem.
Finding out "how" or "why," however, is the principal function of qualitative research including especially the use of focus groups which involves observing interactions between a limited number of people rather than posing a series of questions to an individual in an in-depth interview.
These constraints are possibly related to information processing, which is the principal function of the nervous system.
