Algae

We all know what alga is, right? It’s that slimy green stuff that grows on the surface of a stagnant pond, or on the bottom and sides of your swimming pool if you’re not on top of chlorinating.

In Latin, the name alga means “seaweed,” and yet not every type of algae takes the form of a weed, or lives in the sea. Some varieties live in soil and can withstand long periods without water, while others live in snow or even inside other animal species.

Though scientists agree that there are four types of algae, each is distinguished by different pigmentation, the classification of all but one type remains precarious.