Answer: A
Evolution is the idea that species change over time, and natural selection is a mechanism by which evolution takes place.
Answer: D
Explanation: The villi increases the surface area for food absortion. Each villus has a network of thin and small blood vessels close to its surface. The surface of the villi absorbs the digested food materials.
Answer:
New discoveries in the treatment of cancer do not only centre on conventional medicine. In our haste to get to grips with a cure for cancer, natural products may be overlooked and dismissed in the fight against such an aggressive disease.
In December, the Academy of General Dentistry reported that a new study had found that simply swishing green tea around the mouth halts the growth of new oral cancer cells and breaks down and kills existing oral cancer cells. The antioxidants (polyphenols) in the tea work to remove the free radicals or oxidants and prevent gene mutations, and as an added bonus, the polyphenols can kill cancerous cells without harming normal cells and inhibiting their growth. Similarly, a chemical found in tomatoes may prevent or treat oral cancer and one derived from soybeans has been found to shrink abnormal growths that lead to cancer. While these are not cures, their activity may in the future lead to therapies that compliment conventional treatment modalities.
Perhaps combining ancient remedies with Western scientific advances is the way forward to finding an effective cure for cancer. Combrestatin – a cancer-fighting drug made from the bark of an African tree – is performing with dramatic effects in tests. The active ingredient extracted from the bark attacks the blood vessels that grow with tumors, while leaving normal blood vessels alone.
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