The algae used in space research is

$Ulothrix$ produces

The cell wall of algae is composed of:

Give differences: Brown Algae (Phaeophyceae) and Red Algae (Rhodophyceae).

Which characteristic indicates that two species of algae are closely related?

Assertion : Red algae contribute to the production of coral reefs.
Reason : Some red algae secrete and deposit calcium carbonate over their walls.