Which is not an echinoderm?
a)sea star
b)sea urchin
c)sand dollar
d)spider

An echinoderm is a marine invertebrate. Starfish, Sea urchin, and Sand dollars are all echinoderms. A spider is an arachnid. Which means a spider is *NOT* an echinoderm.

D) Spider

Hope this helps. :-)

D)spider

Explanation:

Starfish, Sea urchin, and Sand dollar, all of following are echinoderms. A spider is a an arachnid.

white blood cells or wbc s are mainly 2 types-

1.agranulocytes

2.granulocytes

the monocytes or macrophages of agranulocytes , dendritic cells which are accessory leucocytes, and b cells which is one type of lymphocytes   identify the antigens present on the pathogen's surface. these three cells are called antigen presenting cells(apc) which are phagocytes and destroy the antigens by secreting antitoxins. besides this leukocyte is always plays vital role in the immunity of the body.