If a neutral aluminum atom (al, Z = 13) becomes al + ¹³ it means that this A) lost 1 electron
B) lost 3 electrons
C) gained 1 electron
D) gained 3 electrons

At an oceanside nuclear power plant, seawater is used as part of the cooling system. this raises the temperature of the water that is discharged back into the ocean. the amount that the water temperature is raised has a uniform distribution over the interval from 10° to 25° c. what is the standard deviation of the temperature increase?