A deficiency of riboflavin can be primary - poor vitamin sources in one's daily diet - or secondary, which may be a result of conditions that affect absorption in the intestine, the body not being able to use the vitamin, or an increase in the excretion of the vitamin from the body.
Substantial evidence means more than a mere scintilla. It means such relevant evidence as a reasonable mind might accept as adequate to support a conclusion.. Richardson v. Perales, 402 U.S. 389, 401 (1971).
There are two types of evidence in a criminal trial: direct evidence and circumstantial evidence. Both direct and circumstantial evidence carry equal importance in a criminal case. Direct and circumstantial evidence are presented to the court by the defense and the prosecution in an attempt to prove their version of the facts in question.