14. amphibians have adapted to the challenge of distributing oxygen more
efficiently to all cells by
a. developing a double-loop circulatory system
b. breathing more quickly
c. breathing only out of water
d. developing a one-way respiratory system

Amphibians have adapted to the challenge of distributing oxygen more

efficiently to all cells by  developing a double-loop circulatory system. Hope that helps! :)

answer: i say it foxes

explanation:

you need to give us the answer options to for me to offical decide.

phylogenetic tree is the tree of life or evolution tree. it shows the different branches of evolution. the sequence goes like tissues - coelom - backbone - endoskeleton - segmentation