I think you forgot to give the options along with the question. i am answering the question based on my knowledge and research. "One group of bears was less highly evolved less than the two other groups and was destined to die out" is the one that explains why only one group of bears were extinct. I hope the answer has helped you.
Answer:
Number of wolves, and harshness of winter.
Explanation: I took the test
Natural selection is the process by which an organism uses its traits to survive and reproduce. In this mechanism of evolution, organisms have favorable traits for survival and reproduction. The more adapted an organism is to its environment, the more likely it is to have heritable traits that are passed down to new coming offsprings, and really, this also applies for the likeliness of the organism to survive and reproduce in general. The more these heritable traits are passed down and used with offspring, the more common the favorable traits are in the community.
You just have to describe on how the cell structure will describe themselves .
