A muscle cramp is a sudden, painful contraction of a muscle, during which movement is difficult. What is happening at the cellular level during a muscle cramp? A.
A lack of calcium causes the sarcomeres to lock together, preventing relaxation.
B.
Myosin and actin do not fully detach, so the muscle cannot relax.
C.
The motor neuron does not send a signal, so the muscle cannot relax.
D.
The proteins in the myofibrils become denatured, preventing relaxation

Two students are working together on an experiment that measures the effect of different liquid fertilizers on the thickness of plants’ stems. which is most likely to result in the greatest amount of error in their scientific experiment? a. one student measures the plant stem widths by using calipers. the other student measures the widths of the same plant stems again by using a different pair of calipers. b. one student measures the plant stem widths by using calipers. the other student types the measurements as they are taken into a computer spreadsheet. c. one student weighs liquids for the experiment by using a calibrated scale. the other student weighs liquids for the experiment by using a different calibrated scale.