Answer:
This was an observational study.
Step-by-step explanation:
Given is that parents of children completed a questionnaire on the child’s light exposure both at present and before the age of 2 years.
This was an observational study since there is no treatment or control group.
We know that treatment, control groups or treatment groups are not specific to randomized control experiments.
Additive identity property
Answer:
1/5
Step-by-step explanation:
The volume of a cylinder is pir^2h. So the answer is pi*4^2 times 4. 64 pi.
