The phrase "all of which challenge" is correct and usable in written English.
It can be used to refer to multiple items or concepts that pose a challenge or difficulty.
Example: "The new policies, all of which challenge our current practices, require immediate attention from the management team."
Alternatives: "each of which poses a challenge" or "all of which present difficulties".
Abortion rights groups say the real goal of these laws, all of which challenge Supreme Court precedent, is to get another case before the court in the hopes that the justices will further restrict abortion rights.
This is evidenced by the continued variability across the study area in terms of government-sponsored healthcare, and constraints in the clinics in terms of staffing, privacy, and patient loads, all of which challenge the access-related assumptions of healthcare decentralization.
From the rise of peer-to-peer lending models, mobile wallets, digital investment advisory, to the bitcoin revolution, today's digital disintermediation comes in many forms – all of which challenge banks to innovate.
A hanging-drop environment with its high cell-to-media ratio leads to nutrient deprivation and hypoxia and the environment turns acidic, all of which challenges tumor cells.
Other celebrated cases have been the notorious Luton post office murder, Broadwater Farm, the family of Blair Peach, the Orgreave miners, the Newham Seven and the Bradford 12 - all of which challenged the integrity of the police or the inadequacies of the appeal system.
None of which challenge the status quo.
The Freedom From Religion Foundation currently has 11 ongoing lawsuits, three of which challenge schools' usage of prayer and religious materials.
He doesn't even flinch when I press him on certain questions, many of which challenge his self-narrative of victimization.
Youth who participated in interviews spoke of non-consensual image sharing incidents in their circles, corporate tracking, and government surveillance of social media as problems that they had to accept all of which challenges adult views of youth as uninterested in topics of privacy, or ignorant about the consequences of personal data misuse.
Furthermore, this vitality is enhanced when it considers a range of democratic claims not discussed here, all of which equally challenge the fundamental frameworks of conceptions of democracy, justice, and their interrelationship: these include the struggles of aboriginal peoples, the disabled, women, and more.
At the same time, Brazil, China, Ethiopia, and India are experiencing the effects of climate change -- more frequent drought and floods, higher temperatures, and increasingly erratic weather -- all of which will challenge their ability to produce enough food and to sustain expanding human and animal populations.
