Cerebrospinal fluid is secreted by choroid plexuses in the ventricles and reabsorbed by arachnoid villi in the

Cerebrospinal fluid is secreted by choroid plexuses in the lateral, third and fourth ventricles and reabsorbed by arachnoid villi in the superior sagittal sinus.

Cerebrospinal fluid is a clear white fluid and it is present in the spinal cord and brain. For the central nervous system it acts like a shock absorber. Sometimes leak of this fluid happens due to some defect in the skull.

the nitrogen cycle provides nitrogen to the ecosystem from the atmosphere, ground and oceans. nitrogen is an important component of complex molecules such as amino acids and nucleotides, which lead to the creation of proteins and dna, the building blocks of all life. plants absorb nitrogen in the form of ammonium, nitrate ion and, on rare occasions, as amino acids. animals receive nitrogen necessary for biological processes from feeding on living or dead organic matter.