True / False / Not Given

Decide whether the statement is True, False, or Not Given.

Urban green roofs, in which vegetation is planted on the tops of buildings, are increasingly used in cities to manage environmental challenges. They can absorb rainwater that would otherwise overwhelm drainage systems, reduce the temperature of buildings in summer, and provide habitat for insects and birds. Some studies suggest they can also lengthen the life of the roof beneath by shielding it from sunlight and temperature swings. Installing a green roof, however, usually costs more upfront than a conventional one, and the structure must be strong enough to bear the additional weight of soil and plants when saturated with water.