Great examples: One example that comes to my mind is: some animals, such as the sea turtles, produce enuff offspring that even without protection or care enough will survive to adulthood to continue the speices. but other species US, humans, produce few young ones, but we need extensive care from our parents until we are self-sufficient. subhaAllah if it wa snot for our parental love and nurishments we would not have survived..
all this reminds of the famous hadith when it coms to Parental Obedience: where a man was told, having helped his aged mom with her tawaf around the Baytullah isnot enough. even if he carries her on his shoulders 70 more times around the Baytullah..it would roughly equivalent to his mother's one night's lost sleep..thus, we can't repay our parents for their kindness, nomatter what we do in this life for them wouldnt be enough!.