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.
The proteins in the myofibrils become denatured, preventing relaxation.
C.
Myosin and actin do not fully detach, so the muscle cannot relax.
D.
The motor neuron does not send a signal, so the muscle cannot relax.

The law of spontaneous generation states that the living forms can grow from the non-living objects. The examples of this law were believed to be the arrival of maggots on meat, and dust from the flies. This law was believed to be true for an extended period of time. During those times, the microscope was not invented, and hence, people were unaware about the existence of the living organisms that cannot be seen with the naked eyes (microorganisms). This led to the people believe in the spontaneous appearances of life forms.