Question

21- What is the type of body cavity where the organs are surrounded by tissue layers which suspend and protect the internal organs?

Group of answer choices

Coelom

Pseudocoelom

Acoelomate

22- These animals were the first to make it onto land ~460 million years ago.

Group of answer choices

Arthropods

Flatworms

Roundworms

Molluscs

23- This flexible rod like structure found in all chordate embryos is replaced by the vertebral column in most vertebrates.
Group of answer choices

notochord

dorsal, hollow nerve cord

pharyngeal clefts

post anal tail

24- This embryonic chordate structure develops into the brain and spinal cord in most Chordates.

Group of answer choices

dorsal, hollow nerve cord

notochord

pharyngeal clefts

post anal tail

25- The embryonic structure develops into gills in some chordates.

Group of answer choices

pharyngeal clefts

post anal tail

notochord

dorsal, hollow nerve cord

26- This unique chordate structure likely evolved for swimming and persists in many adult chordates but is a vestigial structure in our primate lineage.
Group of answer choices

post anal tail

pharyngeal clefts

notochord

dorsal, hollow nerve cord

27- In this filter feeding worm-like nonvertebrate chordate, the four unique embryonic structures persist into adulthood.

Group of answer choices

lancelet

tunicate

lamprey

hagfish

28- In this suspension feeding nonvertebrate chordate, the tail, notochord and the dorsal, hollow nerve cord all cease to exist in the adult animal.

Group of answer choices

tunicate

lancelet

lamprey

hagfish

29- What two unique features do all (and only)mammals share?
Group of answer choices

hair and mammary glands

teeth and four chambered heart

endothermic and closed circulatory system

vertebrae and thoracic breathing

30- These aquatic filter feeding animals lack true tissues and organ systems.
Group of answer choices

sponges

jellies

sea stars

polycheate worms

Answer 1

21.coelom

A coelom is a hollow, fluid-filled cavity found in many living things, where it acts as a protective cushion for their internal organs. In some animals, such as worms, the coelomacts as a skeleton. The coelom also allows the internal organs to move and grow independently of the outer layer of the body wall.

22. Arthropoda

The first fossil arthropods appear in the Cambrian Period (542 million to 488 million years ago) and are represented by trilobites, merostomes, and crustaceans.

23.notocord

In sub-phylum Vertebrata, the notochord present in embryos gets replaced by a cartilaginous or bony vertebral column in adults.

24. dorsal hollow nerve cord.

The dorsal hollow nerve cord derives from ectoderm that rolls into a hollow tube during development. In chordates, it is located dorsally (at the top of the animal) to the notochord. The nervecord found in most chordate embryos develops into the brain and spinal cord, which comprise the central nervous system.

25. Pharengeal clefts

Pharyngeal slits are openings in the pharynx that develop into gill arches in bony fish and into the jaw and inner ear in terrestrial animals.

26.Post anal tail

The chordate tail contains skeletal elements and muscles.

27.Lancelet

Under cephalochordata

Adult lancelets retain the pharyngeal slits, notochord, dorsal nerve cord, and post-anal tail, which are all characteristic of chordates.

28. Tunicates

Tunicates are classified as chordates, only the larval form possesses all four common structures. Adults only maintain pharyngeal slits and lack a notochord, a dorsal hollow nerve cord, and a post-anal tail.

29.Hair and mammary glands

There are only three characteristics uniqueto mammals. The three characteristics are mammary glands, hair and three middle ear bones. Othercharacteristics often thought to beunique to mammals are found in other species including birds, insects and reptiles.

30,Sponges

.Sponges lack true tissues, have no body symmetry, and are sessile; types are classified ... The majority of sponges are filter- feeders