Nervous System Central & peripheral systems
drag and drop ang where
Nervous System & Circulatory System
Nervous System & Respiratory Syster

x would be the most and the least would be y because there are more fruit   and seeds than flock z has insects

desert perennials often survive by remaining dormant during dry periods of the year, then springing to life when water becomes available. most annual desert plants germinate only after heavy seasonal rain, then complete their reproductive cycle very quickly.