Patches of Red and yellow

I do not know why. In the world of Nature, certain colors appear to go only with stronger or weaker tints of themselves or with just one other color and at most with two. Maybe it's a matter of conservation of energy and resources. Certainly energy is a scarce resource and hence, wherever possible, not to be wasted. Is that why duality appears to be a recurrent principle of the observable world here on earth: stem and root (upper and lower) leaves and flowers (producer and consumer), and within the reproductive part of the same flower or between the reproductive parts of flowers from different plants of the same species, male and female pollens (active and passive), and flowers and seed (parent and child) and within the same flower, petals and stamens (attractive assistants and centre of attraction), with the petals in one color and the stamen in another. Whatever the reason for this may be, it's certainly something that I observed at the flower show.

This clusters of flowers have red petals, red buds and red seed pods.

These too have red petal and red stamens

And likewise these smaller flowers

And this

And these.

These flowers also have red petals but yellow stamens which when withered would turn into a much darker black.

This one too is like those above.

This flower has red petals, whitish stems for its stamens topped by yellow at its tips

So is this other flower

And these

And these.

And this. Why only red and yellow? To look more beautiful or attractive?