The existence of water

The existence of the medium heavy chemical elements, like Oxygen, Nitrogen, Carbon, etc. that are the main ingredients to form proteins.

The existence of a long lasting stable heat source, the sun

Atomic properties that allow formation of long chain molecules to carry information that can be replicated like DNA.

The medium heavy elements, it is now known, are produced only in large fast burning stars that at the end of their burning time, when the nuclear fuel in their interior is finally exhausted explode in gigantic explosions, called SUPERNOVA EXPLOSIONS and distribute the elements produced out of hydrogen in their interior during the burning, into the space environment where they can conglomerate to form new solar-planetary systems that now contain these elements.

The strong nuclear force, if it were weaker by about 10 % the next nucleus beyond hydrogen, the DEUTERIUM NUCLEUS could not form. With out Deuterium stars could not begin to burn and build the medium heavy elements. Stars would not be possible. Life would not be possible.

If the strong force, on the other hand were 10% stronger, all hydrogen in any forming star, hydrogen being by far the most abundant element in the universe, would quickly have formed Helium. Then only large short lived stars could exist, those that can burn Helium. No long living stars like the sun, which can burn Hydrogen, would exist. There would not be enough time for life to evolve near such stars before their fuel is exhausted.

If the electromagnetic force were a few percent different from what it is, the delicate binding of the rungs that hold the DNA-molecule together would not work. Large selfreplicating molecules would not be possible. Stable propagation of life would not be possible.

There are other such surprising coincidences in this universe that make it special. It is important here to realize that the examples given all have to do with the possibility in our universe that stars of the kind we have in this universe can form.