Animal Classification Quiz

Which phylum is characterized by having the simplest body design and being almost all marine?

• Phylum Porifera

• Phylum Cnidaria

• Phylum Annelida

• Phylum Mollusca

Answer explanation

Phylum Porifera is characterized by having the simplest body design and being almost all marine. These organisms, also known as sponges, have a porous structure and lack true tissues and organs. The other options, Cnidaria, Annelida, and Mollusca, have more complex body designs and are not exclusively marine.

What is the main characteristic of the body design of sponges?

• Asymmetry

• Radial symmetry

• Bilateral symmetry

• Segmented body

Answer explanation

Sponges are characterized by their asymmetrical body design, which sets them apart from other animals with radial or bilateral symmetry. This unique feature allows sponges to adapt to various environments and efficiently filter water for nutrients. The other options, radial symmetry, bilateral symmetry, and segmented body, do not accurately describe the main characteristic of sponges' body design.

Which phylum has defined tissues and organs, and a digestive system with only one opening?

• Phylum Porifera

• Phylum Cnidaria

• Phylum Annelida

• Phylum Mollusca

Answer explanation

Phylum Cnidaria is the correct choice because it has defined tissues and organs, as well as a digestive system with only one opening. The other options, such as Phylum Porifera, Phylum Annelida, and Phylum Mollusca, do not possess these specific characteristics.

What are the two body forms found in cnidarians?

• Medusa and polyp

• Larva and pupa

• Male and female

• Head and thorax

Answer explanation

Cnidarians, a group of aquatic animals including jellyfish, corals, and sea anemones, exhibit two distinct body forms: medusa and polyp. The medusa form is free-swimming and bell-shaped, while the polyp form is sessile and cylindrical. These two forms represent different stages in the cnidarian life cycle, allowing them to adapt to various environments and ecological roles.

What specialized cells do cnidarians use to capture food?

• Collar cells

• Germ cells

• Stinging cells

• Nerve cells

Answer explanation

Cnidarians, which include organisms like jellyfish and sea anemones, use specialized cells called 'stinging cells' to capture their food. These cells contain a barbed, thread-like tube that can deliver toxins to immobilize or kill their prey. This makes 'Stinging cells' the correct answer to the question.

Which phylum includes flatworms and tapeworms?

• Phylum Porifera

• Phylum Cnidaria

• Phylum Platyhelminthes

• Phylum Annelida

Answer explanation

Flatworms and tapeworms belong to the Phylum Platyhelminthes. This phylum is characterized by soft-bodied invertebrate animals that are bilaterally symmetrical and lack body cavities. Other options like Phylum Porifera, Phylum Cnidaria, and Phylum Annelida do not include flatworms and tapeworms.

What is the main characteristic of tapeworms?

• No circulatory system

• Complete digestive system

• Closed circulatory system

• Segmented body

Answer explanation

Tapeworms are a type of parasitic worm that live in the intestines of some animals. One of their main characteristics is that they do not have a circulatory system. Instead, they absorb nutrients directly from the host's intestine. This is why 'No circulatory system' is the correct answer to the question about the main characteristic of tapeworms.

Which phylum includes earthworms, leeches, and polychaetes?

• Phylum Porifera

• Phylum Cnidaria

• Phylum Platyhelminthes

• Phylum Annelida

Answer explanation

The question asks about the phylum that includes earthworms, leeches, and polychaetes. The correct answer is Phylum Annelida. This phylum is known for its segmented worms, which include the mentioned species. The other options, Phylum Porifera, Phylum Cnidaria, and Phylum Platyhelminthes, do not include these species.

How do annelids rely on gas exchange?

• Through gills

• Through lungs

• Through diffusion in the skin

• Through a respiratory system

Answer explanation

Annelids, such as earthworms, rely on gas exchange through diffusion in their skin. They do not possess specialized respiratory structures like gills, lungs, or a respiratory system. Instead, they have a moist, permeable skin that allows oxygen to diffuse directly into their body and carbon dioxide to diffuse out, facilitating respiration.

Which phylum includes parasitic intestinal nematodes like Ascaris lumbricoides?

• Phylum Porifera

• Phylum Cnidaria

• Phylum Platyhelminthes

• Phylum Nematoda

Answer explanation

Ascaris lumbricoides is a parasitic intestinal nematode, which belongs to the Phylum Nematoda. The other options, Phylum Porifera, Phylum Cnidaria, and Phylum Platyhelminthes, do not include parasitic intestinal nematodes like Ascaris lumbricoides. Therefore, the correct choice is Phylum Nematoda.