In the Northern Hemisphere the reason that cold fronts are often
preceded by rain and cloudy weather
which quickly clears to reveal bright,
clear skies and sunshine, accompanied
by colder temperatures is primarily
due to the fact that-
A low pressure systems that push
cold air south often accumulate
unstable moisture in front of them.
B high pressure systems that push
cold air south often accumulate
unstable moisture in front of them.
C water cannot evaporate in very
cold air, so rain storms cannot
develop behind cold fronts.
D winds only blow on higher
temperature days.

The upper forelimbs of humans and bats have fairly similar skeletal structures, whereas the correspondingbones in whales have very different shapes and proportions. however, genetic data suggest that all three kindsof organisms diverged from a common ancestor at about the same time. which of the following is the mostlikely explanation for these data? a) humans and bats evolved by natural selection, and whales evolved by lamarckian mechanisms.b) forelimb evolution was adaptive in people and bats, but not in whales.c) natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy.d) genes mutate faster in whales than in humans or bats.e) whales are not properly classified as mammals.