Algae with holdfast, stipe and leaf-like blades

Explanation

The correct answer is Laminaria. Laminaria is a type of brown algae that is characterized by its holdfast, which anchors it to surfaces; a stipe, which acts like a stem; and leaf-like blades that are used for photosynthesis. These features are not present in the other options: Volvox forms colonies and lacks these structures; Polysiphonia has a different, filamentous structure; and Ulva, while having a leaf-like appearance, does not have a stipe or holdfast.