In adolescent brain development, myelination and maturation occur in sequence, proceeding from the .

Myelination and maturation occur in sequence, proceeding from the BRAIN STEM and CEREBELLUM to the FRONTAL CORTEX

Explanation:

Myelination is the process of coating the axons of every neurons with myelin (a fat coating) in order to protect the neurons and effectively conduct impulses.

Myelination begins before birth and is not completed until adolescence.

The process moves from back to the front or from the brain stem to the frontal cortex.

organisms that lack symmetry are called asymmetrical and belong to phylum porifera/sponges.

organisms with specialized stinging cells belong to phylum cnidaria. stinging cells are called cnidoblast cells.

cnidarians show two morphological forms : polyp (sessile) and medusa (mobile)

filter feeding is observed in porifera members.  

alternation of generation is observed in coelenterata or cnidaria. there is alternation of asexual polyp form and sexual medusoid form. it is also referred as metagenesis.

emerging idea only occurs as a raw idea that could appear out of nowhere. meanwhile, to reach scientific consensus , that idea must be structured and tested over and over again through various experiments. the scientific consensus transforms the raw idea into idea that is more reliable through the process of scientific elimination.