Which feature in Access is used to control data entry into database tables to help ensure consistency and reduce errors?

What are procedures that keep a data base current

In excel - calculate the actual increase/decrease from first quarter to the second quarter then subtract subtract first quarter value from second quarter total then divide result by first quarter value

If an appliance consumes 500 w of power and is left on for 5 hours, how much energy is used over this time period? a. 2.5 kwh b. 25 kwh c. 250 kwh d. 2500 kwh