Hypothesize what type of environments make being autotrophic, heterotr

Hypothesize what type of environments make being autotrophic, heterotr

Hypothesize what type of environments make being autotrophic, heterotrophic or mixotrophic an advantage to a protist.Many algae are photosynthetic like plants. Why then are they not classified as such?Some protists are colony forming. Hypothesize why this may be an advantage or disadvantage.