Answer:
c. observational study
Step-by-step explanation:
<em>Researchers compare the rates of autism for children who did and did not receive the standard measles-mumps-rubella vaccine, to see if the vaccine might be responsible for autism in some children.</em>
This study design in the above scenario is observational study because the researcher are obviously observing whether the vaccine is affecting the children. Note that Observational study is like experiment which attempts to understand the cause and effect relationships on a subject.
Answer:

Step-by-step explanation:
So we have the equation:

First, distribute the left side:

Add values on the left side:

Add 7 to both sides. The right side cancels:

Subtract 2x from both sides. The left side cancels:

Divide both sides by -6:

Therefore, x equals -3.
So the volume of the cylinder = pi r^2 * h
Height = 4 feet tall
Radius = 1 foot
So just do pi * 1^2 * 4
3.14 x 1^2 x 4 = 12.56 cubic feet
Answer:
the answer is big and your dad knows the answer is B a use Desmos amen