Why is it important to strengthen deep back muscles as well as abdominal wall muscles?

One of the reasons that stars are so large is because

Error analysis: what might be the reason that some of your percentages didn't exactly match your predicted results? gametes aren't responsible for inheritance. mice don't have large litters, so the sample size was not large enough. the wrong type of mice were used.

Creating new things to solve problems and improve life depends on the close interaction of which two fields?