An unmanned spacecraft has been sent to another planet to detect other life forms that might be quite different from those on Earth. If the probe could only send back one still picture, which property or properties of life would be observable in a picture?

The presence of water

Explanation:

Any evidence of water that might appear on the still photo would be a clear indication of life on the planet. This is because scientists believe that for life to thrive elsewhere as it has done here on Earth, it needs water. Water is necessary for fertilization of reproductive cells for some organism, and for others it is where their developing young starts life from. For most, all life biochemical system needs a certain level of moisture to function properly.