Has there been a single trace or evidence about life on Mars? If so can you please provide me the link?

There is no single artifact or analysis to date conclusively proving life previously or currently exists on Mars. However, as our technology expands and our exploration of Mars advances, scientific findings are indicating that the possibility of life at some point existing on the planet is trending towards a more positive outlook.

Discovering that radiation levels only a few inches below the surface are low enough not to be a killer detriment to life doesn't prove life exists or existed, but it does weaken the argument that life simply couldn't exist due to surface radiation and the lack of a magnetosphere.

Discovering that large quantities of water ice locked up in the soils of Mar's polar regions doesn't prove life exists or existed there, but it weakens the argument that life couldn't exist due to a lack of water molecules.

Discovering that the soil of Mars along the equatorial regions during the summer season can be as warm as 70 degrees F, even though the air temperature remains hundreds of degrees below zero, doesn't prove life existed or can exist, but it weakens the argument that life couldn't exist due to extreme low temperatures.

In essence, the more we discover and learn, the harder it is to write off the possibility that life would have somehow found a way to survive on the red planet. Because all of these discoveries are trending positive, the outlook of life on the planet in past or present terms is also trending positive in the same way.

Perhaps at some point we may come across discoveries that will turn the trend around to the negative, but so far it doesn't seem to be heading that way.

Life was found to have been present on Mars at one time.

Allan Hills 84001 (commonly abbreviated ALH 84001) is a meteorite that was found in Allan Hills, Antarctica on December 27, 1984 by a team of U.S. meteorite hunters from the ANSMET project.

Scientists announced that it contained evidence for microscopic fossils of Martian bacteria. On August 7, 1996, U.S. President Bill Clinton made a formal televised announcement to mark the event.

Due to public outcry, the ANSMET scientists retracted their announcement.

In November 2009, a team of scientists at Johnson Space Center reasserted that there is strong evidence that life may have existed on ancient Mars, after having reexamined the meteorite using more advanced analytical instruments now available, in light of the objections that had been made since the biogenic hypothesis for the biomorphs first had been put forward.

Overall, the team concluded that: “None of the original features supporting our hypothesis for ALH84001 has either been discredited or has been positively ascribed to non-biologic explanations.”

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No, there is no proof whatsoever, and given the level of radiation at the surface it seems unlikely (but not impossible) that any life could survive on the surface, but that does not rule out the possibility of life under the surface. However, regarding the lack of proof, it is well worth remembering an old saying: "Absence of proof is not the same as proof of absence", and remember that all the probes we have sent there have only been able to examine a very small portion of the planet, partly due to their slow speed, but mainly due to the immense area they have to explore.

There's alien artifacts on Mars suspiciously designed to resemble rocks.

Although it was said that the Viking landers had not found life, a review of the data with modern computers says that they had.

Unfortuantly not really, so may point to this but it seems to be just a rock

http://www.space.com/21396-mars-rat-curiosity-rove...

Not yet and don't expect any miracle in near future.