Answer:
<em><u>A. Neither the subjects nor the researchers can bias the results.</u></em>
Explanation:
As described, a double- blind study is one in which the researcher and his study does not know the person receiving the actual treatment.
Researchers can be bias in their studies as they seek to establish and fine tune results in the way the best favors them. A double-blind study helps to bridge this gap to prevent bias that might be introduced into an experimental set up or while interpreting results.
B. Similar bacteria or protozoa which group together.
The answer is amyloid beta. They clump together and form plaques. The formed plaque can block signals transmitted from one cell to another cell. In addition, the plaque can cause swelling, especially in the area where it is formed. It can also digest the disabled cells. This type of plaque is very common among patients with Alzheimer's Disease.