DNA is the molecule that carries genetic information of a given organisms. Genetic variation is the changes that occur in the genome of an organisms to help an organism adapt well to the environment, however, they might also be disadvantageous. The variation in DNA sequences are useful in building a tree of life because DNA sequences are similar in closely related organisms and less similar in less closely related organisms.
So, "weather is the day-to-day state of the atmosphere, and its short-term variation in minutes to weeks. People generally think of weather as the combination of temperature, humidity, precipitation, cloudiness, visibility, and wind. But climate is the weather of a place averaged over a period of time, often 30 years." Hope I helped!
Antibiotic resistance happens when an antibiotic lost its ability in controlling or killing bacterial growth. At this moment the bacteria are already resistant to the antibiotic and are multiplying even though the drug is present. This is a natural phenomenon.
B is the answer if not B then C
Fossils can give information about past environmental conditions by showing the type of animal they belonged to. If a scientist found a whale fossil in a desert, he/she could assume that the desert was once an ocean as whales only live in oceans. If someone found a fossil of a lizard that inhabited trees, in the middle of the ocean, then he/she could assume that the ocean didn't exist at one point and instead, there might have been a forest in it's place.
Hope this helps!