Why does left hemisphere control right side of body
Answers
It’s called decussation. It means that if you want to raise your right hand, the left side of your brain issues the command to do that. If someone touches your right shoulder, your left brain senses that.
Weirdly, there’s several exceptions to this rule. Some cranial nerves decussate and some do not.
The olfactory system (smell) isn’t reversed at all. The visual system is only partly reversed; each eye sends some information to each side of the brain. Sounds are analyzed on both sides of the lower portions of the brain but on only one side of the cortex, as shown in this diagram.
Everyone who takes a neuroanatomy class finds the whole thing weird but most students have so much material to learn during that course that the weirdness just becomes one more thing to memorize.