An antigen . View Available Hint(s) An antigen . is a foreign molecule that evokes a specific response by a lymphocyte induces development of white blood cells in the bone marrow is a protein attacked by an invading microorganism is a protein molecule that helps defend the body against disease could be an invading bacterium

Is a foreign molecule that evokes a specific response by a lymphocyte.

Explanation:

Antigens can be defined as molecules that can bind to antibodies, triggering immune responses(by the action of lymphocytes).

The immune system's basic function is to discriminate between proper antigens (autogenous) and non-proper antigens (heterogeneous), in order to prevent attacks by the immune system to molecules in the body itself.

Antigen can also be defined as any substance foreign to the organism that triggers the production of antibodies.

They are usually proteins or polysaccharides that can be found in the envelopes of viruses, bacteria, fungi, protozoa and parasitic worms.

the unequal cytoplasmic division that  results  in  one egg  and three polar bodies ensures that a fertilized  egg has  ample nutrients  forits journey  to  the uterus.