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.
A scale is a selection of certain notes within an octave. The first scale that we will discuss is the major scale. The major scale is constructed with this formula. W's represent whole steps and h's represent half steps. Let's build a C Major Scale. Our starting note will be C. From the C, we will take a whole step to D. From the D, we will take another whole step to E.