If by humans visiting you mean , Which planet's have had humans land on that planet the answer is none. The only other place in space that humans have visited is the moon.
No one has walked on Mars because it is a technologically challenging and expensive endeavor. Sending humans to Mars requires overcoming numerous obstacles such as developing advanced life-support systems, spacecraft capable of long journeys, and landing safely on the Martian surface. Multiple government space agencies and private companies are currently working on plans to send humans to Mars in the near future.
It is illegal to use humans. Rats and mice are inexpensive and easy to keep.
People decide to explore planets using robots, rovers, and other forms of technology due to the risks and challenges involved in sending humans on such missions. Robotic exploration allows for collecting data, conducting experiments, and gathering information that can inform future human missions. Additionally, sending robots is often more cost-effective and efficient than sending humans.
The evolution over millions of years from tree dwellers to land bipeds.
Since scientists were not sure what would happen to humans in space, dogs were used as substitutes for experimental for data gathering.
Homo sapiens
the moon
Most scientists believe that humans originated in Africa.
At this time there is no current mission to send humans to live on the moon.
Humans
Humans are stupid and yeast makes bread.
-- cost -- popular support
-- cost -- popular support
no
the person will sufocate and die
Nothing. We cannot prevent tornadoes.