The flowers functions to ensure pollination by bringing together the sperm and egg. They also confer protection to the ovule and developing embryo inside a receptacle and protect the developing seedling.
The letters of DNA pair up because they form hydrogen bonds: each contains hydrogen atoms, which are attracted to nitrogen or oxygen atoms in their partner
Creative persistence is often useful when one is designing an experimental paradigm for example. It is useful tweaking different parameters of an idea which is much easier when one is creative - this is also at the core of scientific research very often.