Causes. Sunburn results when the amount of exposure to the sun or other ultraviolet light source exceeds the ability of the melanin to protect the skin. Melanin is the skin's protective coloring (pigment).kin cancer usually appears in adulthood. But it is caused by sun exposure and sunburns that began as early as childhood. You can help prevent skin cancer by protecting your skin and your children's skin from the harmful rays of the sun.
The angiosperms, or flowering plants, are one of the major groups of extant seed plants and arguably the most diverse major extant plant group on the planet, with at least 260,000 living species classified in 453 families (Judd et al., 2002; APG II, 2003; Soltis et al., 2005).
Angiosperms Flowering plants (Magnoliophyta) are the most successful of all plant groups in terms of their diversity. The group includes more than 250,000 species, and at least 12,000 genera. This group is usually referred to as angiosperms because, as their name implies, their seeds are enclosed in a carpel (in a vessel). The carpel is the primary feature that distinguishes angiosperms from gymnosperms.