The answer is <u>fishes</u>. Fish are unique in the aspect that they are the only vertebrates that blood circulates directly from respiratory organs to body tissues without returning to the heart first.
Explanation:
This is because the atom that ’donate’ the electrons and the one that ‘accepts’ the electrons – to become ions – will share an electrostatic association and form an ionic bond. So in reality, the atoms are only transferring electrons between themselves rather than “losing and gaining” electrons. When the ionic bonds are broken, such as in chemical reactions, the atoms go back to neutral (regain their electrons) and form new associations with other atoms to form new compounds.
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Answer:
The most abundant type of pollution in national parks at that time was air pollution and it had begun to reduce biodiversity as organisms were leaving polluted areas for cleaner ones, or they simply were not able to survive.
Answer:
The correct order would be:
A vaccine introduces a weakened flu virus into the body.
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The immune system identifies antigens on the weakened flu virus.
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Antibodies are produced, which bind to the weakened flu virus and signal immune cells to destroy it.
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The actual flu virus enters the body, and lymphocytes recognize the antigens.
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Antibodies are quickly produced and allow the body to fight off the infection.
Vaccination or immunization is the process which helps in developing the immunity (adaptive) against a particular pathogen or microorganism.
It includes the administration of antigen, weakened or heat-killed microorganism (such as flu virus) into the patients body. Body's immune system produces naive B and T cells to eliminate the antigen.
This encounter enables the immune system to produce memory B and T cells against that particular pathogen.
In future, whenever the same antigen enters the body, the immune system gets activated quickly due to the presence of memory cells. It enables the body to produce more effective secondary response against the pathogen.
