1. why is earth's temperature just right for life?
a: earth's core is hot enough to heat earth's surface.
b: earth's magnetic field creates suitable temperatures on earth's surface.
c: earth's crust is warmed by heat from the sun
d: earth's atmosphere traps heat from the sun, which makes earth's temperature suitable for living things
2. which of the following statrements accurately explains how earth's atmosphere supports life
a: earth's atmosphere contains 78 percent oxygen, which is essential for life.
b: earth's atmosphere contains 21 percent oxygen, which many life forms need to survive
c: earth's atmosphere contains more oxygen then carbon dioxide
d: earth's atmosphere contains carbon dioxide, which all life forms breathe in

In the future, people will only enjoy one sport: electrodisc. in this sport, you gain points when you cause metallic discs hovering on a field to exchange charge. you are an electrodisc player playing the popular four disc variant. the disks have charges of qa = −8.0 µc, qb = −2.0 µc, qc = +5.0 µc, and qd = +12.0 µc. (1) you bring two disks together and then separate them. you measure the resulting charge of these two disks and find that it is +5.0 µc per disk. which two disks did you bring together? (a) a and b (b) a and c (c)a and d (d)b and c(e) b and d (f) c and d. (2) you bring three disks together and then separate them. you measure the resulting charge of these three disks and find that it is +3.0 µc per disk. which three disks did you bring together? a, b, and c (a) a, b, and d (c) a, c, and d (d) b, c, and d. (3) given the resulting charge of each disk measured in (b) is +3.0 µc, how many electrons would you need to add to a disk of this charge to electrically neutralize it? electrons