Vitamin A is a group of unsaturated nutritional organic compounds, that includes retinol, retinal, retinoic acid, and several provitamin A carotenoids, and beta-carotene. Vitamin A has multiple functions: it is important for growth and development, for the maintenance of the immune system and good vision.itamin A can be found in two principal forms in foods 1  : Retinol, the form of vitamin A absorbed when eating animal food sources, is a yellow, fat-soluble substance. 2  Since the pure alcohol form is unstable, the vitamin is found in tissues in a form of retinyl ester.
pure tone is a tone with a sinusoidal waveform reciting tone such as psalm tone and recitative as in gregorian chants timbre the quality of a musical note or sound that distinguishes different types of sound production tonality a system of music based on a key center or tonic tone control a typically electronic control for affecting frequency content of an audio signal tone linguistics the pitch and pitch changes in words of certain languages tone musical instrument the audible characteristics of a musician s sound
Recently weâve gotten a few questions regarding chord tones: how to work on hearing them, how to aim for them in your lines, and how to connect them when youâre improvising over a chord progression. Understanding the sound and function of chord tones is important to your success as an improviser. However, itâs important to remember that chord tones are not the only aspect of improvising that you need to worry about.