The factor that is responsible for the phenomenon of the blood group B being almost absent in Native Americans whose ancestors arrived in very small numbers about 10,000 years ago would be called the 'founder effect'.
Pistil,carpel,ovary,<span>ovules</span>
Answer:
The active smokers and those getting exposed, that is, passive smokers are at enhanced threat of bacterial infections. Getting exposed to tobacco smoke enhances vulnerability to respiratory tract infections, comprising pneumonia, tuberculosis, and Legionnaires disease.
Smoking compromises the anti-bacterial activities of leukocytes incorporating monocytes, neutrophils, B cells, and T cells, thus, demonstrating the mechanism for enhanced risk of infections.
Correct answer is (D. Once created in bone marrow, they circulate for our lifetime)