Answer: 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
Similar to those performed by the cell organelles in group b
A ecosystem productivity is a rate of generation of biomass.’’I know this because it states.”In economy productivity refers to the rate of generation of biomass in an economy.This shows that the economy its usually expressed in units of mass per unit.
D. They help plants get nutrients and water form soill This is called mutualism.
B.
<span>Pesticides prevent the destruction of crops.
Pesticides have their advantages and strong disadvantages. With the dawn of science, scientists have unearthed biochemicals that can eradicate a set of pests that constantly bombard and hoard plants which are one of the source of food for humans. </span>