Mosquitos are an example of organisms with r-reproduction strategy. This means that they tend to overproduce, have many offspring , but do not provide care for them. This happens because those organisms live in unstable, unpredictable environments, so rapid reproducing is very important. R strategy helps them produce a huge number of offspring, because at least some of them will survive to reproduce.
Elephants are an example of organisms with k-reproduction strategy, meaning that they have few offspring at a time, take care of them and have a long live span. These organisms occupy more stable environments, usually are stronger, better protected and more energy efficient. Their reproductive strategy is to grow slowly and to produce offspring with high probability of survival.