In terms of organisms, photosynthesis occurs in autotrophes that contain the green pigment chlorophyll. This would include the entire plant kingdom, half of the Protista (the algae), & half the Moneran Kingdom (the blue-green algae).
A standard twin mattress is 39 by 75 inches. A king is 76 by 80 inches. This means that a headboard for a king bed is going to be about 76 inches or wider, plenty wide enough to go along the length of a twin bed. Headboards are often slightly wider than the bed for which they are made.
A typical twin size mattress is 38 x 75 so a twin comforter will be larger than this by several inches in both length and width. There is variety with different manufacturers, etc. King 110x 96 Twin and Full sizes in particular vary considerably in length and slightly in width.