There are different types of observers. Casual observers differ from scientific observer. Seeing and observing are two different things. Not that everybody seeing is actually observing the thing.
A casual observer just sits back and watch for something to happen while a scientific observer comes up with some hypothesis to work on it.
The correct answer is pollution.
Answer: Unlike unicellular archaea and bacteria, eukaryotes may also be multi cellular and include organisms consisting of many cell types forming different kinds of tissue.
Explanation:
A fish swims with it's fins and breathes under water with it's gills.
