Select the phrase(s) from the given three options which can be used to form a single sentence from the two sentences given below, implying the same meaning as expressed in the statement sentences. The given options may or may not be starters.
A. Many insect groups have adapted to virtually every terrestrial environment.
B. They survive extinctions and then diversify by quickly adapting to new situations and opportunities that appear after biodiversity crises. 1. Because many insect groups… 2. Therefore, they survive... 3. So they survive…

The sentences share a cause-effect relationship - A tells us that many insect groups have adapted to every terrestrial environment, and B gives the effect of this - they survive extinctions and then diversify by adapting to new situations. 1 is correct as BECAUSE is used to show causation - “Because many insect groups have adapted to virtually every terrestrial environment, they survive extinctions and then diversify by quickly adapting to new situations and opportunities that appear after biodiversity crises.” 2 is correct as THEREFORE is used to show causation - “Many insect groups have adapted to virtually every terrestrial environment, therefore, they survive extinctions and then diversify by quickly adapting to new situations and opportunities that appear after biodiversity crises.” 3 is correct as SO is used to show causation - “Many insect groups have adapted to virtually every terrestrial environment, so they survive extinctions and then diversify by quickly adapting to new situations and opportunities that appear after biodiversity crises.”