Pia mater (soft inner layer of the dural membrane system) The pia mater, which contains vessels, is the innermost layer of the three meningeal membranes. ... Furthermore, it creates the choroid plexus, a network of bold vessels, which enter the brain ventricles and produce the cerebrospinal fluid (CSF).
I think the correct answer is C. Less than 10% of rain falls in a dry desert. Desert biomes are known to be the driest of all types of biomes. It receives very or almost no rainfall. Precipitation in a dry desert is about 250 mm per year.
So that over time they can adapt to survive
I do believe it is C hope this helps its been a while since i was leaning about this.....
