Life is what remains undefined till today. How it is being blessed to a small fetus and how it leaves an old body, remains a mystery to man even after so many years of tiring efforts and research on it. We also refer life as the presence of material that is vital for life like water, oxygen, etc. As man is critical about things he has and curious about things he does not have which makes him called human: a construct of questioning mind and searching hands. The closest to Earth and most favorable to support life after our Earth is said to be Mars. So it is the planet most studied for the evidence of life.
Different researches and investigations have found different evidences common to that of Earth, for example; methane signatures and certain biological activities. Scientists have hypothesized that there are living things present on Mars which tolerate the extreme conditions. Also, scientists worked on some subsurface chemical bioreactor processes and related it to life on Mars. These reactions may support the surface environment, they say. The NASA scientists Stroker and Lemke strongly support life presence under the surface of Mars through their evidences. The fluctuation of methane signatures and sulfate jarosite indicates to some life existence even in hot springs. So the presence of water may be predicted from it. Hence, it leads to the assumption that some microbial life is present. Captured images of Mars from satellites suspected some moving objects in the air as well as on the surface but the existence of life is not yet confirmed.
Some theories may say that signs that we are working on about life on Mars, are due to living organisms, transferred from Earth. The point of discussion arises from the fact that meteorites from Mars have also reached Earth so it could be some vice versa case as well. But the meteorites that reached Earth contain in themselves some microbes as investigated by NASA. Some evidences show that the mud volcanoes are present on Mars which may indicate life there. These volcanoes bring out the inside material and may help in finding what is present inside. The search will continue that may not result in any strong proof but it would at least add to our never ending knowledge.