Arthropods

they all have exo skeleton

No. A unicellular organism is an organism made up of ONE CELL, so they're all microscopic. Microscopic means that you can't see it it without a microscope. And you can see a sea urchin, so it is not microscopic, so it's not unicellular.

An arthropod is an invertebrate animal having an exoskeleton (external skeleton), a segmented body, and jointed appendages. Arthropods are members of the phylumArthropoda(from Greek ἄρθρον arthron, "joint", and ποδός podos"foot", which together mean "jointed feet"), and include the insects, arachnids, crustaceans, and others. Arthropods are characterized by their jointed limbs and cuticles, which are mainly made of α-chitin; the cuticles of crustaceans are also biomineralized with calcium carbonate. The rigid cuticle inhibits growth, so arthropods replace it periodically by molting. The arthropodbody plan consists of repeated segments, each with a pair of appendages. It is so versatile that they have been compared to Swiss Army knives, and it has enabled them to become the most species-rich members of all ecological guilds in most environments. They have over a million described species, making up more than 80% of all described living animal species, and are one of only two animal groups that are very successful in dry environments - the other being the amniotes. They range in size from microscopic planktonup to forms a few meters long.

Arthropods are characterized by segmented bodies, an exoskeleton made from chitin, and joint appendages. They have an internal body cavity (hemocoel) and an open circulatory system which employs hemolymph, a fluid that does not distinguish between interstitial fluid like lymph and oxygen carrying fluid like blood as in most vertebrates. They use a copper-based oxygen carrier molecule instead of the iron-based hemoglobin, which floats unbound around in the hemolymph and is not bound to blood cell proteins. They do not have a dedicated and separate branch of their circulatory system just to oxygenate; internal organs (and cells) are simply bathed in this fluid. Their nervous system is 'ladder-like' on their ventral surface, and their brains formed around the esophagus from fused segment nerve ganglia.

Some of these adaptations of butterflies

are that they can fly

and also they pollinate flowers.

The true count of living arthropods at any given moment on Earth is unknown but some estimates place it at around ten quintillion (10,000,000,000,000,000,000) which is over a billion for every human.

The head, thorax and abdomen are one so a three peice body, three pirs of legs and I can not think of the third...

yes, because it has its skeleton on the outside (its shell)

They have muscles like us, except theirs are smaller and are connected to the inside of their exoskeletons, instead of wrapping around the endoskeleton like we have.

Domain: Eukarya
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Superorder: Heterobranchia
Order: Pulmonata

The name for phylum Arthropoda is derived from "jointed legs" or jointed feet, and arthropods live up to that name. Because of the rigidity of the exoskeleton, joints are apparent in any of their mobile appendages; not just legs but some specialized appendages like swimmerets for aquatic arthropods, antennae, wings, all evidence some kind of jointing. Legs themselves may have specialized adaptations; some insects hear or taste with special organs on the legs or feet. Some crustaceans have legs bearing claws (chela) called chelipeds.

An arthropod is an invertebrate animal having an exoskeleton (external skeleton), a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda, which together mean "jointed leg", and include the insects,arachnids, and crustaceans. (Ant, Spider and Crab)

No, krill are a type of fish that whales feed on. They are very small.

Yes dragonflies are arthropods. Insects are by far the most populous species of arthropods, including ants, beetles, butterflies, dragonflies and grasshoppers. Over 1 million arthropodic insect species have been identified, and the number grown on a nearly daily basis. These insects are characterized by a triple-segmented body containing a head, thorax and abdomen. Insect arthropods have 6 or more legs, two antennae and lateral, compound eyes.

Arthropoda are the most diverse and arguably the best distributed in species, with the highest count known of described species in any phylum. Over a million species under the phylum have been described and biologists estimate that millions of species have yet to be described. Most of these are in the Insecta class; and about 400,000 of them are beetles (coleoptera).

The actual count of living arthropods at any given moment on Earth is unknown but some estimates place them around ten quintillion (10,000,000,000,000,000,000) which is over a billion for every human. By count, insects are over half of all living animals and by some estimates may constitute up to ninety percent of all living animals on the earth. In biomass, krill (an arthropod crustacean) are believed to have the highest of any animal, weighing in from up to half to three quarters of a billion tonnes, and thus having a huge significance in the food chain.

They are (by definition) considered insects. They are in the insect order Lepidoptera and are classified with insects because they have a head, thorax, and abdomen. They also have three pairs of walking legs, antennae and a pair of wings-which are the characteristics of most insects.

They are having jointed limbs, a segmented body, an exoskeleton, and a well-developed nervous system. YOUR WELCOME PERSON!

Yes, it is classified as an insect.

Yes, it is classified as an insect.

Yes, it is classified as an insect.

Yes, it is classified as an insect.

Yes, it is classified as an insect.

Yes, it is classified as an insect.

Legs and exoskeletons were extremely useful, as these enabled the creatures to resist gravity, which is not a concern in the bouyancy of water.

That it's hungry.. >.<

three paits of jointed legs.

Edit: Be Real Man. The real answer is that the water pushes heavy stuff up to make them lighter in water then in land.

edit: really you both are rong the real answer is:Afaik this depends on the animal in question. Some insects, for example, do not grow in size at all when adults and thus avoid this problem. Animals that do shed their exoskeleton can move, the underlying soft exoskeletong along with the internal pressure of the animal are enough to facilitate this. But at least many crayfish (and likewise many otehr arthropods that shed their exoskeleton) hide until their exoskeleton has hardened again - that is, they can move, but will not unless they really have to. They just hide in some nook and wait.

And what comes to other disadvantages of chitious exoskeleton: it allows muscles to attach only inside of the exoskeleton, quite unlike human muscles for example work. This provides poorer strength production, which is why arthropods cannot really grow much larger than what we see around us. For similar reasons, virtually all the largest arthropods live in water, because there you need less strength to move heavy weights.

Even though we know that ants are mighty strong compared to their size, human-sized ants would collapse even udner their own weight and they could not carry a hundred or so times their weight like small ants do!

an arthropod sheds it old exoskeleton when it has grown to a point where it needs a larger exoskeleton. This process is called ecdysis.

They can change colors, yes. They can change from looking like a golden lady bug to looking like a lady bug by controlling the amount of moisture present under their shell.