The results of a filter test (consisting of nine yes/no questions) which support this conclusion are below, followed by evidence to support the answers.
Isod, nodir canlyniadau prawf hidlo (a oedd yn cynnwys naw o gwestiynau syml) sy’n ategu’r casgliad hwn, ac yna cyflwynir tystiolaeth i ategu’r atebion.