- a polysaccharide gel and dead cells.
- a collagen-like gel and suspended cells for various functions.
- spicules composed of silica or calcium carbonate.
- multiple pores.
The large central opening in the parazoan body is called the:
Most sponge body plans are slight variations on a simple tube-within-a-tube design. Which of the following is a key limitation of sponge body plans?
- Sponges lack the specialized cell types needed to produce more complex body plans.
- The reliance on osmosis/diffusion requires a design that maximizes the surface area to volume ratio of the sponge.
- Choanocytes must be protected from the hostile exterior environment.
- Spongin cannot support heavy bodies.
Cnidocytes are found in _____.
- phylum Porifera
- phylum Nemertea
- phylum Nematoda
- phylum Cnidaria
Cubozoans are ________.
While collecting specimens, a marine biologist finds a sessile Cnidarian. The medusas that bud from it swim by contracting a ring of muscle in their bells. To which class does this specimen belong?
- Class Hydrozoa
- Class Cubozoa
- Class Scyphozoa
- Class Anthozoa
Which group of flatworms are primarily ectoparasites of fish?
The rhynchocoel is a ________.
- circulatory system
- fluid-filled cavity
- primitive excretory system
Annelids have (a):
- true coelom.
- no coelom.
- none of the above
A mantle and mantle cavity are present in:
- phylum Echinodermata.
- phylum Adversoidea.
- phylum Mollusca.
- phylum Nemertea.
How does segmentation enhance annelid locomotion?
- Segmentation creates repeating body structures so the entire organism functions in synchrony.
- Segmentation allows specialization of different body regions.
- Neural segmentation allows annelids to localize sensations.
- Muscle contractions can be localized to specific regions of the body to coordinate movement.
The embryonic development in nematodes can have up to __________ larval stages.
The nematode cuticle contains _____.
- skin cells
- nerve cells
Crustaceans are _____.
Which of the following is not a key advantage provided by the exoskeleton of terrestrial arthropods?
- Prevents dessication
- Protects internal tissue
- Provides mechanical support
- Grows with the arthropod throughout its life
Echinoderms have _____.
- triangular symmetry
- radial symmetry
- hexagonal symmetry
- pentaradial symmetry
The circulatory fluid in echinoderms is _____.
Which of the following features does not distinguish humans as a member of phylum Chordata?
- Human embryos undergo indeterminate cleavage.
- A spinal cord runs along an adult human’s dorsal side.
- Human embryos exhibit pharyngeal arches and gill slits.
- The human coccyx forms from an embryonic tail.
The sister taxon of the Chordata is the _____.