At rest, the cytoplasmic Ca2+ concentration in a typical skeletal muscle cell is about 70 nM. At the peak of the skeletal muscle cell contraction phase, the cytoplasmic Ca2+ concentration is approximately:(A) 10−1 M(B) 10−3 M(C) 10−6 M(D) 10−9 M(E) 10−12 M Checking your answer...