Protists are a group of diverse eukaryotic, predominantly unicellular microscopic organisms that may share certain morphological and physiological characteristics with animals or plants or both. They have a nucleus that contains their genetic material, DNA. Some protists are autotrophic and can make their own energy through photosynthesis, while others are heterotrophic and consume other organisms for food.
Out of the three sentences given, only the second one is accurate. The first one is false because not all protists are unicellular and microscopic; some are multicellular and macroscopic, such as kelp. The third one is false because not all protists make their own energy through photosynthesis; some are heterotrophic and depend on other sources of organic matter. Therefore, the correct answer is:
They have organelles, so protists are eukaryotic in nature.