Explanation:
1] ADAPTATION : WE HAVE BEEN ADAPTING A DOG AS A PET.
2] BIODIVERSITY : BIODIVERSITY IS THE VARIABILITY AMONG LIVING ORGANISMS FROM ALL SOURCES INCLUDING TERRESTRIAL, MARINE, AND OTHER AQUATIC ANIMALS
3] ISOLATION : THE PROCESS OR FACT OF ISOLATING OR BEING ISOLATED
4] VARIATION : DIFFERENCE BETWEEN ORGANISMS OR PLANTS
SO, THIS IS YOUR ANSWER
I believe it would be the leaves because that helps collect water! :)
All of these are necessary, but what you need the most I would say is
D. Movement
Without movement, your body can stiff up, causing muscle problems which can lead to many various things.
That would be B. Cell Wall
Hope this helps.