Answer:
D. your first day of school
Explanation:
No thats dangerouse to the poeple
Answer:
Physical activity helps prevent chronic illness, which reduces the need for medical treatment.
Explanation:
They could make a matrial that wolnt rust, and that will not wear down/ break
Answer: Refractory period of the cardiac action potential
Explanation:
Unlike the skeletal muscle which can be reactivated before it reaches a contraction, cardiac muscle must wait before it is almost completely relaxed to be activated again (because of its long refractory period), so one cannot make an increase in strength of contraction with a high frequency of stimulations.
