Selma wants to find out at which temperature streptococcus bacteria reproduce the fastest. selma places the same size sample of the bacteria on 10 different petri dishes filled with nutrient agar. she then places each dish in different incubators which are all set at different temperatures. after three hours, selma removes the dishes from the incubators and observes the size of the bacterial colonies. what is the variable in selma's experiment?

answer; ///(b) it is composed of four protein chains and four heme groups;

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.