What is the advantage of csf for brain and spinal cord

In which of the following ways is the function of the surface of a microsphere similar to the function of an actual cell membrane? a.both make it possible for the conditions in the interior to be different from the conditions outside. b.both provide a barrier that keeps water from flowing across it so the interior remains dry. c.both separate the rna that forms in the interior from any rna that might form in the environment. d.both can actively move molecules into the interior or out into the surrounding environment.

If a young male's body is just beginning the process of producing sperm, when is it likely that he would ejaculate mature, viable sperm"

What is true about all plutons? they form below earth’s surface. they form near earth’s surface. they form above earth’s surface. they cut across other rock layers.