The phrase "a previous study indicate" is not correct in written English.
It should be "a previous study indicates" to agree in number with the singular noun "study."
Example: "A previous study indicates that regular exercise improves mental health."
Alternatives: "a prior study suggests" or "an earlier study shows."
The results of a previous study indicate that the mitochondrial DNA (mtDNA) of the green alga Volvox carteri abounds with palindromic repeats, which appear to be selfish elements.
In addition, results from a previous study indicate that nulliparous women with the A2A2 genotype have higher mean levels of serum estradiol than those with the A1A1 genotype [ 46].
However, results from a previous study indicate that when non-genotyped sibs are included in the analysis through pedigree information (as in the current study), accurate estimates of genetic variance can still be obtained for larger selectively genotyped samples [ 13].
A previous study indicate that interventions such as cognitive-behavioral therapy and relaxation techniques may be effective in reducing stress, anxiety, and burnout in healthcare workers when compared to no intervention [ 24].
A previous study indicated that increased litter abundance results from summer warming in the Arctic, reflecting the increased abundance of evergreen trees and low-growing and tall shrubs40.
A previous study indicated that CBD attenuates the imbalance between Bcl-2/Bax, upregulating the anti-apoptotic protein Bcl-2, which in turn maintains the integrity of the outer mitochondrial membrane, in an animal model of multiple sclerosis46.
A previous study indicated that the DEC was a powerful identifier of submaximal effort of shoulder external rotation in normal volunteers.
A previous study indicated that in some African countries significant portion of protein is obtained from wild meat.
However, a previous study indicated that the maximum biting force (400 N) was better for occlusal adjustment with intercuspal clenching.
A previous study indicated that a primary treatment process has limited capability to remove and/or degrade antidepressants residues in wastewater [15].
