The bird's feathers .
Well it depends on what you mean by "signs". Almost every single animal on the planet would and could identify some sort of sign given either by another animal of the same species or the sign (warning) of a predictor of the animal. So in order to answer the question correctly, or most accurate would be to be more specific about your meaning of "signs" .mjc..
Generally a combination of these features: tough exoskeletion made of chitin, jointed appendages and segmented bodies. There is no single feature as any of these features are not exclusive to Arthropoda e.g. Annelida also have segmented bodies.
A single cell animal is an animal with only one cell. They are also called Eukaryotic.
Every single animal.
The human body is many animal cells. Bacteria are single celled organisms. The cell is the smallest partical that is living. Animals are more then one animal cell. Plants are more then one plant cell. An organism can be single celled or multicellular, but all life consists of cells. In higher organisms, the cells diferentiate and are not capable of living alone. Protists are single celled organism which can have animal and / plant characteristics.
There is no single geographic feature that separates China from the rest of the world.
It is used to identify single strains of bacteria therefore, tracing the outbreak of infections.
Likely the largest single geographical feature in Europe are the Alps. The mountains reach heights of over 15,000 feet above sea level.
Probably Mont Blanc
bjb,nbk.
a single celled animal is called an amoeba
Not a single animal drowned in the Ark.