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.
Twin beds are used for bunk beds too. Overall dimensions: 39 wide x 75 long. Width per person: 39. Pros: Because of its small size it will fit easily into smaller bedrooms. Twin sheets are the least costly of all sheet sizes and are available in lots of patterns. It's easy to make a twin bed. Cons: A standard size is too short for many adults.