A answered. Atrial fibrillation can be caused by a number of different things that predispose the heart to arrhythmias. Most commonly, longstanding high blood pressure is the cause. Other causes include heart disease such as blockage in the coronary vessels or diseases such as pneumonia or COPD.
A board, typically with a hole for the thumb, which an artist can hold while painting and on which colors are mixed. 2. a. The range of colors used in a visual medium, in a picture, or by an artist: a limited palette.
Color, defined through: value (how light or dark it appears) hue, how cool or warm it appears, and chroma, how bright or muted it appears. Through these three elements, were developed the four principal groups, palettes called: Spring, Summer, Autumn, and Winter.