Myosin is a contractile protein found in muscles that is composed of three pairs of subunits, two heavy chains, and two pairs of two different types of light chains, for a total of six subunits. myosin contains what level(s) of protein structure?
a) primaryb) primary and secondaryc) primary, secondary, and tertiaryd) primary, secondary, tertiary, and quaternary

Answer is D. primary, secondary,tertiary and quaternary

Explanation:

Myosiis known to be a protein that is found in the muscles. It helps in conversion of Adenosine Triphosphate, ATP into mechanical energy. This makes the muscle to contract or relax.

The contractile proteins are the proteins that bring about the sliding of the contractile fibers of the muscle.

The four levels of protein structures are the primary, secondary, tertiary and quaternary. They can only be differentiated or distinguished  from one another based on the degree of complexity in the polypeptide chain.

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.