Answer:
When people get vaccinated they there will be less change of transfer of communicable diseases
By staying healthy and practicing good hygiene
The answer is Sodium Fluoride
A. He should add shells that are different colors, but the same size and type, to the tank and observe which shells the hermit crabs choose.
Durning an experiment you need to keep everything the same but only change the certain things based on your theory.
Such as how the student wanted to see if the color attracted the crab. If he had changed the size and type of the shell then the crab would have chosen the bigger one as they tend to grow into larger shells.
Explanation:
it is the tendency relatively stable equilibrium between interdependent elements especially as maintained by physiological processes.
