B. 'peripheral proteins' are present, not 'peripheral steroids'.
Answer:
Thirty patients with acne volunteer to be treated with either a medicinal lotion
or a normal moisturizing cream. This type of experimental design is called
a clinical trial.-B.

Last option: Preserve an ecosystem

• The establishment of a bird reservation is a way to preserve an ecosystem because reservation provides suitable environment to organism. A healthy ecosystem means large number of biodiversity.
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