lizards and all different types of mammals

how many tissue layers do the phylum arthropoda have

Lady bugs, stink bugs,ect.

pollinate plants

Cnidarians do not have a circulatory system. Different parts of the body receive nutrients not via a stream of blood but through diffusion from seawater into their tissues. They are neither cold, nor warm-blooded - they have no blood.

Bees are classified as arthropods because of their characteristic segmented bodies, an exoskeleton made from chitin, and joint appendages.

Largest group of invertebrates with an exoskeleton. For instance, crustaceans, insects... etc.

Yes, molluscs fit into the group known as protostomes.

As part of nature's clean-up crew, Goliath beetles are helpful. They feed on rotting fruits, dung, material from dead trees, and the remains of dead animals.

Biramous

goods

Yes

class cyclostomata are without jaws

there eg are :

petromyzon

myxine

The lower an organism is in the food chain the greater its population.

Yes, lobsters are one of the creatures that are capable of regenerating limbs. Also, lobsters have been known to cut off their own limbs as a survival mechanism too.

Chitin has two notably good qualities as an exoskeleton. Since it is a type of protein, it is relatively easy for arthropods to make. And it is quite tough. Its properties are similar to the protein keratin, which is used by mammals for making hair, nails, and horns.

Yes. A nematode is covered by a tough cuticle that is periodically shed through ecdysis.

1. Trilobites

2. Chelicerates

3. Myriapods

4. Hexapods

5. Crustaceans

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.