Answer:
Anything that would be interacted with by a living being.
Explanation:
We have no clue what could affect a living thing if something was changed.
A rock could be placed on the side of a mountain, and this rock rolls down the mountain later on, killing Albert Einstein.
A Mere few inches long piece of metal could be left on the ground, shielding 2 t-rex egg from the meteor that wiped them out perfectly, causing most species such as humans not to exist.
Anything could have an unknown consequence, because it is possible for the littlest things to have the largest effects.
