Follicular and luteal phase lengths. â variability of menstrual cycle. attributable to follicular phase. â  Mean cycle length ranges from 27.3 to 30.1 days between ages 20 and 40 years, follicular. phase length is 13-15 days, and luteal phase length is less variable and averages. 13-14 days1-3.
Any sequence of seven successive natural notes, such as C-D-E-F-G-A-B, and any transposition thereof, is a diatonic scale. Piano keyboards are designed to play natural notes, and hence diatonic scales, with their white keys. A diatonic scale can be also described as two tetrachords separated by a whole tone.
Scales refer to a series of notes that go in an ascending and descending manner. The major scale is the foundation from which all other scales are formed. A C major scale begins with a C and ends with a C. The same rule applies with the rest of the keys where a D Major Scale begins and ends with a D and so on. The notes on a major scale is numbered from 1 to 8, this signifies the intervals. C = C - D - E - F - G - A - B - C.