Mutualism is when both sides benefit. The hummingbird gets nectar and the flower is benefited because the hummingbird that has been to other flowers carry pollen on its body which spread the flower when it sucks its nectar, therefore pollinating the flower in the process.
A species must be able capable of surviving and reproducing despite changes to food sources, climate, or threats from predators.
Cells need to reproduce for growth, repair, or replacements. Cells divide whenever a tissue / organ / organism is growing or needs repair.
Hope this helps :)
