Answer:
Spirogyra is a genus of green algae that belong to the order Zygnematales. These free-flowing, filamentous algae are characterized by ribbon-shaped chloroplasts that are arranged in a helical manner inside the cells. So the name is derived from the spiral arrangement of chloroplasts in these algae.
Explanation:
Valence electrons. They are the outermost electrons
There are about 250 chemicals that are harmful including carbon monoxide and ammonia.