Sebastion the Phisics master
N.a.S.A sent spacectafts to mares called mariner spacecrafts.
The different tools are satellites, probes, telescopes. and spacecrafts.
Although several spacecrafts have been sent to Venus, no alien spacecrafts have been discovered on its surface.
Niagara Falls is a natural feature; it was not built by humans.
Computers were built for, of course, Humans.
Early humans built shelters to protect themselves from the elements, predators, and other threats. Shelters also provided a sense of security and a place to rest and store food and belongings. They were essential for survival and helped early humans adapt to different environments.
spacecrafts
If it is built by humans, maintained by humans, for the benifit of humans then it cannot be 100% safe
With humans flesh
Fuel is so useful to spacecrafts because without the fuel the spacecraft would not go.
humans haven`t been to venus but some unnamed spacecrafts have but they where destroyed within hours because of the heat from the atmosphere. But seven other spacecrafts have done surveys from orbit.