Question

Question 19

19-Which of the following organisms utilizes a single circuit (one atrium/one ventricle) circulatory system?

Group of answer choices

1-fish (actinopterygii)

2-tree frogs (amphibia)

3-iquanas (reptilia)

4-spiny echidna (monotreme mammal)

Question 20

20-Which phylum within the group ‘Bilateria’ is comprised species that are typically radially symmetrical at sexual maturity?

Group of answer choices

1-echinodermata

2-arthoropoda

3-nematoda

4-mollusca

5-platyhelminthes

Answer 1

Question 19.

the answer is option 1-Fish (actinopterygii)

• The actinopterygii have a closed circulatory system with a 2 chambered heart with an atria and a ventricle.This forms a single loop.
• Tree frogs and other amphibia has a 3 chambered heart
• All reptiles have a 3 chambered heart with the exception of crocodie.
• Echidna is a mammal which has 4 chambered heart

Question 20.

The answer is option 1-echinodermata

The echinoderm larvae has a bilateral symmetry which later changes to radial symmetry in the adult form