Question

which describes the greenhouse effect?
an artificial process
a dangerous process
a natural process
a new process

Explanation:

The greenhouse effect is a natural process where certain gases in Earth's atmosphere (like carbon dioxide, methane) trap heat from the sun, keeping the planet warm enough to support life. It's not artificial (has existed naturally), not inherently dangerous (though enhanced by human activities can be problematic, but the natural process is vital), and not new (has been occurring for billions of years). So the correct description is a natural process.

Answer:

C. a natural process