The answer to this is: C) a factor that may affect an experiment or investigation. This is the best answer. A and B can be eliminated. D describes a controlled variable which is more specific than a scientific variable, thus C is the best answer. It is the best description of just a scientific variable. And, The second one is B: Robert Hooke was a famous scientist who experimented with springs (metal coils). He found that the farther you stretched the spring, the larger the force with which the spring pulled back on you.
You can infer that the birds once had a common ancestor but became separated. Mutations in copying their genes stacked and caused changes in the beaks so the birds could be more well off or better adapted in their new environment.
Which damages the environment, also melts thw glaciers so animals such as polar bears lose their habitats and will come extinct at some point.... hope this helps
