B - They have repeating steps
Answer:
B) Viruses are killing some of his B cells and becoming incorporated into the genomes of others.
Explanation:
Epstein-Barr virus causes infectious mononucleosis by following mechanism.
1) Epstein-Barr virus attaches to and infects epithelium of the throat where it replicates and causes pharyngitis.
2) Virions enter the lymphoid vessels and are carried to the lymph nodes. Some virions escape the lymphnode trap and are carried to the bloodstream.
3) Virions attach specifically to B lymphocytes and infect them, producing either latent infection or productive infection.
4)The infected B lymphocytes actively replicate and differentiate into cells producing random immunoglobulins.
5)T cells respond to infection and destroy the lymphocytes replicating EBV vitus.
6) Latently infected B lymphocytes become immortal. They are not attacked by T cells.
The amount of stuff that an ecosystem
1. They have a slimy skin in which the oxygen gets dissolved. 2. The frog have lung instead of gills 3. They have enormous no. of nerves which help them to breathe through skin
