Although the source of this heterogeneity is poorly understood, one explanation could be that diverse tumour vascular biology can exist in a patient.
Reasons for the high rate of sexual assaults among American Indians are poorly understood, but explanations include a breakdown in the family structure, a lack of discussion about sexual violence and alcohol abuse.
Although the mechanisms for tumor evasion of immune response are poorly understood, one viable explanation is that tumor-killing lymphocytes cannot reach the tumor cells in sufficient quantity to keep the tumor in check.
The reasons for the increased severity observed with some influenza strains are poorly understood and possible explanations include an excessive cytokine response [7] [11], a poor immune response due to the strain's novelty [12], [13], and differences in target cell receptor affinity (cell tropism) between human-adapted, seasonal strains and animal-origin pandemic strains [14] [17].
The reason for localized heating beneath such areas is poorly understood, and thus an explanation for the distribution of plateaus of that type is not known.
The concept of mucosal friability, however, is poorly understood and always needs explanation.
The adaptive value of schooling behaviour is poorly understood, but several logical explanations have been advanced.
The causes of this phonetic generalization are, however, poorly understood and several competing explanations have been proposed.
An explanation for poorly understood phenomena in muscle contraction (Section 3) requires better understanding of the incompletely understood molecular mechanisms considered below.
In addition to the well-established pathways of NO signaling, epigenetic mechanisms may provide much-needed explanations for poorly understood context-specific effects of NO.
The interactions of these tetramic acid breakdown products are as yet poorly understood and may offer an additional explanation for the greater than expected immunosuppressive activity of these molecules.
