What two types of macromolecules are the main components of myelin? A. carbohydrates and lipids B. proteins and nucleic acids C. phospholipids and proteins D. carbohydrates and nucleic acids E. water and proteins

Option C.

Explanation:

Myelin are insulating layer or sheath that surrounds axonal part of neurons of the brain and spinal cord . Myelin surrond nerve cells or neurons.

It contain protein and fatty substances. It is Rich in lipids which help in propagation of nerve impulses. The insulation improved the efficiency of signal transduction along the nerves cell.

because the asteroid belt is between the mars and jupiter orbits, it is around 2.2 to 3.2 astronomical units (au) from the sun – which is approximately 329,115,316 to 478,713,186 km. the average distance between objects is a massive 600,000 miles.

explanation:

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.