Question

what are the features of planarians? warm blooded mammals, complex life cycle, hard protective coating parasitic, ribbon - like body, scolex with hook and suckers regenerative abilities, simple body plan, shaped like an arrow

Explanation:

1. Analyze the first option: Planarians are not mammals (they are flatworms), not warm - blooded, and have no hard protective coating. So this option is incorrect.
2. Analyze the second option: The features of "parasitic, ribbon - like body, scolex with hook and suckers" belong to tapeworms, not planarians. So this option is incorrect.
3. Analyze the third option: Planarians have remarkable regenerative abilities, a simple body plan (they are acoelomate flatworms), and their body shape is often arrow - like (or triangular) at the head end. This option correctly describes the features of planarians.

Answer:

regenerative abilities, simple body plan, shaped like an arrow