Answer:
30 minutes.
Step-by-step explanation:
The national academy of science is one of the prestigious institute of the science for the students. This institute is present in United states and is a private organization.
The physical activity is important for the individual health and reduces the chance of diseases. The daily 30 minutes of the physical activity is important for all the individuals and this has been recommended by the institute of science as well.
Thus, the answer is 30 minutes.