aloe leaves--store water
cactus spines--prevent water loss & function as protection (all those prickly things would make for an unappealing meal)
colorful bracts of poinsettas attract pollinators (those red things aren't petals; they're leaves. the little yellow things in the center are the flowers, and they're small and rather unattractive by themselves, so they need the help of those red leaves!)
tendrils--allow plants to "climb" (example: sweet peas)
cactus spines--prevent water loss & function as protection (all those prickly things would make for an unappealing meal)
colorful bracts of poinsettas attract pollinators (those red things aren't petals; they're leaves. the little yellow things in the center are the flowers, and they're small and rather unattractive by themselves, so they need the help of those red leaves!)
tendrils--allow plants to "climb" (example: sweet peas)