Biology.
It amazes me how developments in the material world strongly enhance and preserve life as we know it.
One example: Ultraviolet rays from the sun helped catalyze some chemical reactions instrumental to the propagation of living molecules (via the chemical evolution theory of life). When life evolved to allow carbon-fixation photosynthesis (the one most plants generally perform), these organisms effectively changed the atmosphere from a Hydrogen-dominant to an Oxygen-dominant one. The effect of this was the propagation of the ozonosphere, which in total contrast to the first sentence of this paragraph, protected life from the danger of the sun’s rays to the newer, more delicate forms of life.
Biology really makes one think about how amazing it is that life was able to come about exactly as it has done.
