Phenylketonuria (PKU) is an example of: MCQ with Answer and Explanation

Explanation:
Cerebrospinal Fluid (CSF) is a clear, watery fluid that circulates through the ventricles of the brain, the central canal of the spinal cord, and the subarachnoid space. It provides mechanical protection (cushioning), chemical stability, and waste removal for the central nervous system. CSF is primarily produced by the choroid plexus, which is a network of highly vascularized, specialized ependymal cells located within the ventricles of the brain (lateral, third, and fourth ventricles).

Explanation:
Musca domestica is the common housefly, a dipteran insect. Periplaneta americana is the American cockroach, Drosophila melanogaster is the fruit fly used in genetics, Apis indica is the Indian honeybee. Housefly can act as a mechanical vector for diseases like typhoid, cholera. Scientific names help precise identification.

Explanation:
Calcium is a major component of bones. Vitamin C is water-soluble, iron is for hemoglobin (oxygen transport), iodine deficiency causes goiter, anemia is from iron/B₁₂/folate deficiency.