An experiment was conducted to evaluate the success of an Ebola virus vaccine. The subjects were unaware of the treatment they were given. What is this type of blinding used to prevent? A. Grounds for malpractice suits
B. Subjects assigned randomly to treatments
C. A source of researcher bias
D. Injury to the subjects The placebo effect

The right answer is option B

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15

step-by-step explanation:

we are given the following expression and we are to solve it and find the product:

-13 × (-5)

solving the given expression in the standard order of solving a mathematical expression, beginning with the opening of brackets and then multiplying the terms and changing their signs.

-3 × -5 = 15 (answer is positive because when negative is multiplied with negative, it gives a positive answer)