In class we discussed and example from the book that detailed a fossil record of clams and their snail predators. These species saw an active trend over time in both the thickness of the clams shell and the size of the structures the snail used to pry open the shell. This is an example of . A. sexual selection
B. a coevolutionary arms race
C. a mutualistic relationship
D. an evolutionary stable strategy

answer; ///i believe its: ///(embolus);

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.

yes we can.   a lady urinates from her urethra.