First of all, "the God" is a very subjective factor. It solely depends on individual belief. However, the nature is unconditional nurture of each alive as well as dead elements of cosmos. Here, the nature is not only tree, mountains, waterfall, animals, etc. Moreover, its the combination of the great five supreme elements Earth, Fire, Water, Sky and Air. Along with each and every factor that are, the reason for ours survive.
In other words, nature is our chief caretaker. The ability to adjust to surrounding (congeniality) is a gifted skill of the nature to living elements. In the same way, the living element strives to overcome the unfavourable condition. So, naturally, the living elements are trying to make changes in theme self and surrounding area to convert an adverse component to a favourable one. Because doubt grows with knowledge.
For example, suppose ABC is the first human who has born as result of nature's evolution chain, as told by Charles Darwin. Since he is first and only human, naturally did not think about costume :-). However, he might had faced hunger at first. But is super secret and curious thing of the nature that how the first human has sustained himself as one and only human. This is same doubt as of whether an egg is first or chicken.
Anyway, when he learned the eating, of course, he might have produced unique sound/symbol for that food as an identity. Then they might have developed some sign and accents to exchange/communicate their sentiments. Why not, it happens naturally today too.
As we stand at apex level of evolution of human beings, our mind generates doubt like, who has created the world, the word, name, languages, etc. No doubt every human being has their own curiosity.