What happens when carbon is heated with stem?

What does standard deviation reveal about data? a. the average of all the data points b. which of the data points is most reliable c. how spread out the data points are d. the percent error included in the data

If 10.0 ml of the solution on the right are withdrawn from the 100 ml beaker and diluted again in a similar manner, what is the new concentration? m nacl

Iknow #2 is d. i just need to know why