Cerebrospinal fluid is produced by the
a. choroid plexus.
b. arachnoid villi.
c. frontal sinuses.
d. pia mater.
e. ventricles.

Option A "Choroid plexus".

Explanation:

Cerebrospinal fluid can be defined as the fluid that is found in the brain and spinal cord of human beings. It is a clear and colorless fluid.

The production of cerebrospinal fluid takes place by the specialized ependymal cells that lies in the choroid plexuses which is present in the  ventricles of brain.

The amount of cerebrospinal fluid in a day is 500mL. This fluid acts as cushion that protects the brain from mechanical and immunological protection.

Hence, the correction answer is option A

the organisms are not adapted to live in some communities or habitats.

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.