The primary challenge from Iraq comes in the Mideast.
The primary challenge in designing a case-control study is the appropriate selection of cases and controls.
The primary challenge is that, even after years of efforts to change them, the public perceptions of STEM are largely misinformed and outdated.
"The primary challenge that our side faces right now is the intense social pressure," said Joseph Backholm, 34, the executive director of the Family Policy Institute of Washington.
The primary challenge for anti-slug controllers is robustness.
The primary challenge in protecting data privacy is to handle the malevolent role of the TPA.
The primary challenge to the literature of system resilience is how to measure it qualitatively.
The primary challenge associated with CSim is how to make it practical.
The primary challenge in observing the 21 cm EOR signature is subtracting the strong astrophysical and instrumental foregrounds.
The primary challenge for any autonomous system operating in realistic, rather unconstrained scenarios is to manage the complexity and uncertainty of the real world.
The primary challenge in the initial assessment of a patient with undifferentiated shock is to quickly identify and treat any reversible causes of shock.
