The phrase "a major underlying reason" is correct and usable in written English.
It can be used when discussing the primary cause or motivation behind a particular situation or event.
Example: "The study revealed that a major underlying reason for the decline in biodiversity is habitat destruction."
Alternatives: "a significant root cause" or "a key fundamental reason".
NCDs are a major underlying reason why pregnant women die.
Retsky et al. [ 14] hypothesized that induced angiogenesis after surgery in premenopausal node-positive breast cancer patients is a major underlying reason why adjuvant chemotherapy works particularly well for those patients.
Unfortunately, its title, "Hypothesis: Induced angiogenesis after surgery in premenopausal node-positive breast cancer patients is a major underlying reason why adjuvant chemotherapy works particularly well for those patients", belies this importance.
The major underlying reason is that the knee spring engages more readily in the transverse-mirrored configuration, resulting in this faster and more efficient locomotion.
Dr. Tsai's team also showed that dysregulation of COUP-TFII is the major underlying reason for serious diseases, such as congenital diaphragmatic hernia, congenital heart defects, tumorigenesis and heart failure.
By qualitatively examining the internal motives of firms in the process of becoming a B corporation, and quantitatively testing key factors in these firms' external industry environment – including the shareholder- and stakeholder-focused behaviors of their corporate competitors – we found that there are at least two major underlying reasons why firms choose to seek B Corporation certification.
In this part, the major underlying reasons for owning small area coverage for some of the stations that have less than 0.5 km2 area coverage are displayed based on the service area coverage analysis for 0 800 m walking distance.
Several of the major underlying reasons why significant events occurred, such as knowledge and skills errors or communication difficulties are consistent with previously reported reasons why errors and adverse events occur in both UK and international family practice [ 7, 8, 11, 12].
