Both active solar heating systems and passive solar heating systems a. must face south
b. use pumps and fans
c. reduce the need to use fossil fuels
d. only work during the day

Hmm.

Explanation:

C. Reduce the need to use fossil fuels

( If it's not C, then try D)

slitherio is the original. its the best friend of all middle schoolers. the man you can count any time you have some free time. slitherio is the guy you hang with while you're in the computer lab suppose to be doing "research or whatever". slitherio isn't just a game but a friend.

wormaxio is just a fake trying to squeeze its way into the friend group. trying to pretend its cool and your best pal but how long has it really been there for you, really. it only wants you as friend to boost its social status. wormaxio is just annoying fake pleb. no offense

you and have a wonderful day