The vitamin that is a coenzyme in the transfer of one-carbon units is: MCQ with Answer and Explanation

Explanation:
Cerebrospinal fluid (CSF) is a clear fluid produced by the choroid plexus in the ventricles of the brain. It cushions the CNS, provides buoyancy, removes waste, and maintains chemical stability. Synovial fluid is in joints, pleural fluid in chest cavity, lymph in lymphatic vessels.

Explanation:
The nucleolus is a dense spherical structure within the nucleus where ribosomal RNA (rRNA) is transcribed and ribosomal subunits are assembled. They then exit to the cytoplasm. The cytoplasm is the site of translation. Mitochondria have their own 70S ribosomes but their rRNA is synthesized within the organelle. Golgi modifies proteins.

Explanation:
In roots, the protoxylem (first formed xylem) lies towards the periphery and metaxylem towards the centre; this arrangement is called exarch. In stems, protoxylem is towards the centre, called endarch. Exarch condition is typical of roots. Mesarch is found in ferns. This arrangement aids in understanding anatomical differences between root and stem.