Given that the electricity for home use is 5 cents per kilowatt-hour (kWh), how much would it cost to operate 5 fluorescent 40W light bulbs for the months of April and May if they are on for 3 hours/day? How much less is this than running 5 incandescent 100W light bulbs for 3 hours/day over the same time period?

Without stratospheric ozone, which of the following would most likely occur? i. smog over major cities would be greatly reduced. ii. farms would produce surplus crops because of increased photosynthesis. iii. uv radiation would damage phytoplankton and reduce populations of aquatic consumers. i only ii only iii only i and ii i and iii