Antigen: is a a foreign substance or toxin that causes a immune response.
Antibody: it is a blood protein that is produced in response to an antigen.
White blood cell: also called a leukocyte and is a cell that counteracts against antigens.
Specific: If your're talking about the biology definition then it is, of or pertaining to a species.
Pathogen: a virus or bacteria that can cause a disease.
They are Exosphere,Thermosphere,Mesosphere,Startosphere and Troposphere
<span>The gestation and infant care period increased to allow the brain to develop. </span>
Answer:
Ancient Egyptians may have first domesticated cats as early as 4,000 years ago. Plentiful rodents probably drew wild felines to human communities. The cats' skill in killing them may have first earned the affectionate attention of humans.