what is a common feature of all protists?

they are prokaryotic.
they absorb nutrients.
they require moisture.
they can photosynthesize

They require moisture  is a common feature of all protists

Explanation:

Protists are categorized based on how they eat, how they move and how similar they are to the other eukaryotic kingdoms. Protists are single-celled almost. One can speculate regarding protists as all eukaryotic organisms that are not animals, neither plants not a fungus. They also may seek for food like an animal or photosynthesize like a plant.

Protists are organisms that need moisture to live. They mostly live in aquatic habitats, though they may also grow in moist tree trunks and soil, among other environments. Protists also go through periods of sexual or asexual reproduction, based on their species or seldom their environmental situations.

answer: angiosperms

dicots

angiosperms are highly evolved plants, they produce seeds which are enclosed within in a carple. these are the largest group of plants on earth. they include trees, shrubs, herbs and small flowering plants. angiosperms exhibit a flowering stage in their life cycle. the flower serves the function of reproduction and fruit formation in majority of angiosperms. dicot is the term used to describe flowering plants that have two seed leaves. dicots are plants which develop seeds which split into two parts called cotyledons. each cotyledon contains one embryo.

here, a small purple flower development indicates that the plant belongs to angiosperms and having two embryonic leaves indicates it belongs to dicots.  

b is the correct answer