Question

1) Frogs breathe using A) various absorptive surfaces but with no pneumatic system to ventilate those surfaces. B) gill modifications. C) negative pressure, similar to reptiles and mammals. D) a bird-like circular air circulation. E) positive pressure breathing during which air is forced into the balloon-like lungs. period. 2) Tetrapods originated in the A) Cambrian B) Carboniferous C) Silurian D) Permian E) Devonian 3) Frog singing A) uses the large vocal sacs as resonators. B) involves vocal cords in a larynx. C) is more common in males than females. D) is produced by passing air back and forth between the lungs and vocal pouches. E) All of the choices are correct. 4) Most of our familiar frogs belong to which large family? A) Plethodontidae B) Anuridae C) Hylidae D) Bufonidae E) Ranidac 5) A frog skeleton A) is, like that of crossopterygian, entirely cartilaginous. B) has a vertebral column consisting of only nine vertebrae and a urostyle. C) bears limbs with four digits on each hand and foot. D) has a highly flexible vertebral column, an adaptation for transmitting force from the hindlimbs of the body. E) All of these choices are correct.

Answer 1

Answer 1) (e) positive pressure breathing where air is forced into the balloon like lungs.

The humans or mamals have muscles like the ribs thathelp them to inspire by creating a negativeb pressure inside the lungs but in frogs its not so.

when the frog is in the tadpole form, it does not have lungs and therefore breathes through gills on the bosy, when it matures, it develops lungs which is used to breathe when it is outside the waster and inside the water, it respires through it body surfaces.

Answer 2) Permian

Answer 3) all of the above choices are correct

Answer 4) Ranidec

Answer 5) (b) has a vertebral column consisting of only 9 vertebrae and a urostyle

Frogs infact has a rather hard spine to keep their body stiff helping them to leap.

they also have a thick bony skeleton

the frogs have four digits in the foreleg while 5 in the hind.

therefore (b) is the correct answer.

l hope my answers come of help to you :)