Headache and Fatigue.
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Answer:
About 5billion years ago is the correct option.
Explanation:
Hope this will help you :)
Answer:
Your answer should be B or C.
Explanation:
Answer:
Oxygen is obtained from photosynthesis process.
Explanation:
Oxygen is one of the most important element required for survival of living organism. Living beings inspire oxygen and expire carbon dioxide which is collectively called as respiration and is considered as most important biological process.
Plants prepare their own food through the process called photosynthesis. It is process through which the plants uses carbon dioxide and water as reactants and gives out glucose and oxygen as the end product.
The released product is sugar and gas, in which the sugar is consumed as food by other living organism and the gas called oxygen is used for respiration and other biological process. Thus it can be inferred that oxygen is obtained from process called photosynthesis.
Answer:
True.
Explanation:
Antigen may be defined as the chemical that has the ability to evoke the and immune response and can harm the living organisms. The specific antibody are produced against the immune response.
The antigens has evolved different mechanisms to prevent themselves from them the immune system of the host. The antigenic shift is the most common change that might occur in viruses that helps the antigen to protect itself by changing its genetic material. No anti viral drugs are available for the viruses.
Thus, the answer is true.
