Which two organisms are most closely related?

a. euryarchaeotes and diplomonads

b. brown algae and dinoflagellates

c. brown algae and red algae

d. euglena and brown algae

The cladogram is a diagrammatic representation of relationships between different groups of taxa. It is used to study the evolutionary relationships between organisms.

The correct answer is:

Option B. Brown algae and dinoflagellates

The relationship between organisms can be explained as:

1. Dinoflagellates are commonly termed sea sparkles. The organisms can segregate into the algal bloom and releases toxic substances that are harmful to marine organisms. It has a coiled groove, annulus consisting of the flagellum.

2. Brown algae are a large group of multicellular algae, which includes many seaweeds. The organisms are important as food and are a potential habitat for marine organisms.

3. Dinoflagellates are unicellular algae, whereas brown algae are multicellular organisms. These organisms belong to domain eukarya and are branched from the same node in the above cladogram.

Thus, the correct answer is Option B.

To know more about dinoflagellates, refer to the following link:

link