The phrase "a core activity" is correct and usable in written English.
It can be used to refer to a fundamental or essential task or function within a particular context, such as a business or project.
Example: "Developing a strong marketing strategy is a core activity for our company's growth."
Alternatives: "a key function" or "an essential task".
"For us it is a core activity, not an add-on," says Arnander.
"It has become a core activity of the mainstream population's daily life".
At stake was what constituted a "core activity" for an airline.
"Formula One will always be a core activity, for sound business reasons as well as for historical sporting reasons".
The Guardian, Daily Mail, Times and Economist have all made headway, with varying success, with tablet apps, but the position of the iPad-only The Daily – which laid off a third of its 150 staff at the end of July – suggests that it's not a core activity.
The Ruia family does not regard telecoms as a core activity and is debating whether to sell now or wait for a still higher price in a year or so.Reliance Communications, the country's second-biggest mobile operator, which has been controlled by Anil Ambani since India's biggest conglomerate was split in two in 2005, is interested in buying out both Hutchison and Essar.
Principle 5 defines analysis of practice as a core active learning activity for teachers.
Interestingly, the production of several cellulases appears to be conserved among the species, suggesting that this may be a core-activity for all species.
No. 2 son sees Nessie becoming a Danfoss core activity.
A third core activity is sustainability management and reporting, the development of environment and social performance indicators specially tailored to the finance industry.
Publications often represent an important core activity of those societies.
