For an animal to be extinct none more of that specific species must exist on Earth. This makes it impossible for that species to come back to life.
Answer:
A. Activated B - cells divide to form memory cells.
Explanation:
The vaccine contains the dead version of the respective virus, so that virus will be inactive and it will become easy for the WBC to kill it and antibodies will be formed.
This is done because if we get infected by the virus, our body cells (WBC) will remember that how they killed the first entered virus (the dead version) and it will be easy for them to kill the active virus as they know the antibodies which were formed to kill the inactive virus.
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We see the so called " near side " of the moon. Because the moon spins in the exact rotational period we see the same side of the moon every time we look at it .
Answer:
D. Fossil record.
Explanation:
The fossil record evidences the evolutionary history of life on Earth by tracing the life forms that existed from earlier geological times and remained in the sedimentary rock. Different fossils were dated in the sedimentary rocks of all geological periods. The simplest forms of life were discovered in the oldest rocks, while more complex fossil organisms were found in the newest rocks. In consequence, the fossil record can support the evolutionary process as proposed by Charles Darwin, who indicated that the simplest forms of life evolved in more complex organisms.
