A part of the hepatitis B virus can be synthesized in the laboratory. This viral particle can be identified by the immune system as a foreign substance, but the viral particle is not capable of causing the disease. Immediately after this viral particle is injected into a human, it .

Triggers the formation of antibodies that will protect the body from hepatitis B virus.

Explanation:

A virus is a kind of pathogen that has the ability to cause disease inside the body. A vaccine consists of the dead, apart of virus or weekended form of virus which is injected in the body.

This vaccine does not have the ability to cause disease inside the body but has the ability to trigger the immune response.

The antigens(virus) are usually a part of the protein that causes this immune response. Due to this the immune system produces antibodies and other cells which can take part in response.

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.