Is it possible to breathe on other planets without pressure suits, such as Venus?

 Breathing on other planets, like Venus, without a pressure suit would be extremely difficult and dangerous for humans. Here's why:

1. **Atmospheric Composition**: Venus' atmosphere is mostly carbon dioxide (96.5%) with trace amounts of nitrogen and clouds of sulfuric acid. Humans require oxygen (around 21%) to breathe, so the lack of oxygen in Venus' atmosphere makes it impossible for humans to breathe there.

2. **Atmospheric Pressure**: Venus has an atmospheric pressure that is about 92 times that of Earth at sea level. This pressure is equivalent to being 900 meters (about 3,000 feet) underwater on Earth. Without a suit to protect from this immense pressure, a human would be crushed.

3. **Temperature**: The surface temperature on Venus is extremely high, averaging around 465°C (869°F). This intense heat is hot enough to melt lead and would quickly fry any unprotected human.

4. **Toxic Environment**: Venus' atmosphere is also full of toxic gases, including sulfur dioxide, which would make it lethal to breathe.

In short, without advanced technology like pressure suits or habitats, humans cannot survive on Venus due to the hostile environment, lack of breathable air, extreme pressure, and high temperatures.