a. The links joining monosaccharide residues in a polysaccharide are called bonds.

 Glycosidic bonds.

Explanation:d

Glycosidic bonds are covalent bonds that  join monosaccharides or longer glucose chains to other monosaccharide or carbohydrates to form disaccharides, oligosaccharides and polysaccharides and are named according to the type  of the atom present on the second carbohydrate to be linked. The bond is usually  formed between the hemiacetal of  the first carbohydrate and the functional  group on the second molecule which could be Oxygen-, Nitrogen-Sulphur -, and Carbon -glycosidic bonds.

Examples of  Polysaccharides are Cellulose Starch , Glycogen  formed by the linkage of many long residue monosaccharides connected through  glycosidic bonds.

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.