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).
Examples are pines, cedars, spruces and firs. Some gymnosperms do drop their leaves-ginkgo, dawn redwood, and baldcypress, to name a few. --Angiosperms are a taxonomic class of plants in which the mature seed is surrounded by the ovule (think of an apple).This group is often referred to as hardwoods. Angiosperms are trees have broad leaves that usually change color and die every autumn. Oaks, maples and dogwoods are examples of deciduous trees.xamples are pines, cedars, spruces and firs. Some gymnosperms do drop their leaves-ginkgo, dawn redwood, and baldcypress, to name a few. --Angiosperms are a taxonomic class of plants in which the mature seed is surrounded by the ovule (think of an apple). This group is often referred to as hardwoods.