Answer:
Because humans has not arrived until 20,000 years ago.
Explanation:
The genus homo has been taken to the emergence with the Homo habilis. Homo sapiens has been emerged around 300,000 to 200,000 years ago.
Holen and colleagues in 2017 discovered 130,000-year-old site in California that contain a a mastodon that had been butchered by humans. Some scientists express skepticism because it has been believed that only humans have occupied North America. The Homo sapiens has not arrived until 20,000 years ago.
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 correct answer is amylase
Answer:
4 oxygen molecules
Explanation:
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Since penicillin interferes with peptidoglycan synthesis, it means that the drug will have no effects on archaea.
<h3>Archaea cell walls</h3>
The cell wall of archaea consists mostly of polysaccharides and glycoconjugates. In order words, the cell walls of archaea lack peptidoglycan.
Since penicillin kills bacteria by interfering with the synthesis of peptidoglycan, it simply means that the drug will have no effect on archaea, since they do not have peptidoglycan in their cell walls.
More on archaea can be found here: brainly.com/question/1475001
