The answer you're looking for is [NOTE: MAKE SURE YOU DO 10^-3 TO INDICATE THAT IT IS AN EXPONENT! More often than not the exponent wouldn't come through as an exponent. Example: would look like x3. To signify that it is an exponent you do x(^)3.]
As always, it'll be multiplied by 10. It's evident that the power 10 will be raised to would be the third power given that there is three zeroes. It's also evident that it'll be a negative power since we are dealing with a number/decimal less than one. What solidify this is the fact that we have to move the decimal point to the left three times (moving a decimal point left leads to the exponent being negative and the number of times you move the decimal point is the exponent number. In this case it's -3) in order to make a digit, that isn't zero, in front of the decimal point. 0.00212 -> 0.0212 (1) -> 0.212 (2) -> 2.12 (3)
These systems are defined both by the types of energy and matter they contain and by how that matter and energy move through and between systems. In natural systems, both energy and matter are conserved within a system. This means that energy and matter can change forms but cannot be created or destroyed.