Another interesting advancement in green technology is the idea of green walls and green roofs, which are green because they are made from plants. using plants as part of the building is a great way to make a building green. green walls and roofs reduce the amount of cooling needed in the summer and heating needed in winter. what is the main idea of the fourth paragraph? a) using low-flow toilets, sinks, and shower heads saves water. b) gray water is any type of waste water other than toilet water. c) xeriscaping is landscaping with plants that do not need much water. d) using walls and roofs made of green plants reduce the amount of cooling needed in the summer

D)Using walls and roofs made of green plants help reduce the amount of cooling needed in the summer

Explanation:

The main idea of the fourth paragraph is to show that using walls and roofs made of green plants help reduce the amount of cooling needed in the summer. This is because in horizontal or even vertical buildings, the thermal insulation provided by the green roofing generates energy savings, being able to reduce the internal temperature of the environment by up to 10 ° C.

A green roof is a thin layer of vegetation installed on top of a flat or sloped roof. The vegetation can vary from lawn, shrubs or even trees, depending on the weather and the load capacity of the roof.

wheres the passage with the idiom underlined