The H1N1 and H3N2 viruses both cause the flu, an infectious disease characterized by respiratory symptoms, fever, and body aches. Each year, a flu vaccine that contains H1N1 and H3N2 antigens is developed. An individual who receives the vaccine makes antibodies directed against these antigens.

The flu vaccine is typically about 60% effective against H1N1 flu viruses, but only 30% effective against H3N2 viruses. What is the most likely reason why the flu vaccine is less effective against the H3N2 flu viruses than the H1N1 flu viruses?

A. Infection with the H1N1 virus does not involve an immune system response.
B. Infection with the H3N2 virus does not involve an immune system response.
C. The H3N2 flu viruses mutate more rapidly than the H1N1 flu viruses.
D. The H1N1 flu viruses mutate more rapidly than the H3N2 flu viruses.

i would have a lunch. it's one big package of food, making it one food. : p

estuaries are the partially enclosed coastal bodies of brackish water formed at the mouth of sea where river meets an ocean. it is a transition zone between river and sea water so estuaries are influenced to both marine environment such as tides, waves and to riverine such as flow of fresh water and sediments. the mixing of sea and fresh water provide high level of nutrients, making estuaries a high product habitats.

many estuaries suffers degradation from a variety of human activities like erosion from deforestation, overgrazing, overfishing, drainage and eutrophication.

so from the above statement answers will be

1. false as estuaries are formed due to both brackish and freshwater.

2.true, due to high productivity estuaries are breeding ground for many marine species.

3. direct and indirect activities of man that contribute to pollution and deposition of sediments.