Meninges are membranes that cover and protect the brain and spinal cord.
There are three layers of meninges: Dura mater (closest to the bone), Arachnoid loosely around the brain, Pia mater is closely attached to the brain and spinal cord surface.
there is no clear evidence about plants evolving in the desert, or fossils of any kind of cactus despite their distribution over a large area. But, scientists are of the opinion that they acquired specific attributes millions of years ago, as a response to the vastly changing climate and conditions.
-Desert plant root system
A typical desert plant has a deep root system, which is a specific physical mechanism. As the roots grow deep down the soil, they absorb soil water, which is then transported to the upper portions of the plant.
-Desert plant leaves
Bear small foliage with waxy surface to minimize transpiration (loss of water through stomatal pores), which in turn, helps to conserve water.
C Fossils allow scientists to have an idea of the time scale that traits evolved.
