C: lack of water during long periods..
C. Ice is less dense than water which means water condenses when it freezes allowing the ice in a lake to float on top of the water preventing the water below from freezing.
Answer: Infection occurs when the host is exposed to pathogens. virus uses the cell's metabolism, and replicates itself while destroying the cell or changing the cell's genetic makeup.
Explanation:
- A virus is a miniscule pocket of protein that contains genetic material.
- Viruses pose a considerable challenge to the body’s immune system because they hide inside cells.
- This makes it difficult for antibodies to reach them. Some special immune system cells, called T-lymphocytes, can recognise and kill cells containing viruses, since the surface of infected cells is changed when the virus begins to multiply.
- Many viruses, when released from infected cells, will be effectively knocked out by antibodies that have been produced in response to infection or previous immunisation.
- Antibiotics are useless against viral infections. So antiviral drugs work differently to antibiotics, by interfering with the viral enzymes instead.
Hence virus are the pathogen that use the cell's metabolism. And replicate itself while destroying the cell or changing the cell's genetic makeup. viruses are so simple that they use their host cells to perform their activities for them
Learn more about virues :
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Answer:
D&A
Because the Digestive system breaks down food( which starts in the mouth because of the eynzemes) Then is broken down in the stomach (mechanical digestion) then the water and nutrients are absorbed in the small intestine, in the large intestine the rest of the nutrients are absorbed. Also, I just did the last test and finished this section in science
This is true a theory is an explanation of observable facts and phenomena.
