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.

b tumor cells have a cell wall instead of a membrane

explanation:

tumor cells different from normal cells because tumor cells have a cell wall instead of a membrane.

when it is at an intermediate population density

the  different  of  these  two  are  that  they  differently  handle  their  team.

an  expressive  leader  focuses  on  the  task  at  hand  and  make  sures  that  their  goal  is  achieved.  they  accurately  finish  the  task.  an  instrumental  leader  on  the  other  hand  works  on  the  unity  of  the  group,  they  care  more  about  their  employees.  all  the  while  creating  a  good  environment.