How does human vision occur in our body system?

Question

why does human vision occur?

Answer 1

It occurs so we can get visual responses from environment.
It occurs by our eyes.
Eyes form an image on retina which through Opical nerves sends electrical impulses to Brain (Visual Cortex) where it is intrpreted and we see and understand what we see.
this information is also stored for future reference.
Details of complex processes and names can be found in any Zoology book or Wikipaedia.
hope this piece of information finds use to you.

Answer 2

Science does not claim to be able to currently explain everything, so pointing out that there are some things which it can not yet explain doesn't have much meaning. Science is just a set of tools which establishes reliable ways to determine whether something is true or false once it has been claimed. When dealing with humans, though, there are some particular difficulties. Ethics prevents us from performing many experiments on human beings. To determine with scientific certainty something like, for example, whether blushing is a useful trait which helps humans survive in tribal groups, we would need to isolate multiple groups of feral children, and probably genetically modify some to not be able to blush, then observe them and see how it affects their ability to survive. Obviously, this would be astoundingly cruel and no madman would permit such a thing to be done. Science does give us some tools, though, to help consider ideas that can't actually be objectively tested. If those ideas require accepting something which is obviously false, well, it can't be true. If it being true would lead to contradictions or other things which we can test and see are false, we can know that it cannot be true. I noticed a few of the things in the list also are not 'human traits' because they are not universal. For instance, many cultures do not have 'terrible teens'. We have created that by the way we treat children and adolescents. Superstition can be fairly well-explained scientifically. The human brain operates by forming associations between different concepts. Our brain is a pattern-finding machine and it is very greedy. It finds patterns even where no pattern exists. That leads to common flaws in thinking that all people share. Many of these flaws are summarized as "logical fallacies", such as 'confirmation bias' where people pay attention to things which support patterns they think exist, and ignore evidence that shows the pattern is not real. That can lead to superstitious beliefs, like an athlete believing in "lucky socks" or similar. When they win a game wearing their lucky socks, they say "Ah! See! The lucky socks work!" but when they lose a game while wearing those socks, they say "We would have lost even more badly without the socks". If they actually experimented and kept track of wins and losses both wearing and not wearing the socks, they could see rationally that their belief is not accurate, but few people do such a thing, leading to superstition.

Answer 3

The answer to your question is very complex and many people would have a difficult time comprehending the complete answer. I refer you to books encompassing the subject of " neurobiological basis of behavior"......from there you will surely be able to expand your knowledge on the subject.