Final answer:
Brown algae are Stramenopiles, primarily marine, noted for their distinctive pigmentation from chlorophyll a and fucoxanthine, and possess structures like holdfasts for attachment. They have two different types of flagella, distinguishing them as members of the Stramenopiles group.
The correct answer is option d. Have two flagella.
Step-by-step explanation:
Brown algae, also known as Phaeophyta, belong to a category of organisms called Stramenopiles, characterized by having two different types of flagella. These organisms can vary greatly in size, from the microscopic to the massive, like giant kelp.
They are primarily marine organisms and categorized by several unique features such as having holdfasts, stipes, and blades, which allow them to attach to substrates and perform photosynthesis, though these structures are not true roots, stems, or leaves.
The pigmentation of brown algae comes from a combination of chlorophyll a, chlorophyll c, and fucoxanthine, which gives them their distinctive brown color. Importantly, these organisms are not limited to the marine environment, but that's where they are predominantly found.
They have two different types of flagella, distinguishing them as members of the Stramenopiles group.
The correct answer is options d. Have two flagella.