Atmosphere of Mars energy to escape the planet. In this process the light isotope of carbon (C) is most likely to leave the atmosphere. Hence, the carbon dioxide left in the atmosphere would be enriched with the heavy isotope (C). This higher level of the heavy isotope is what was recently found by the "Curiosity" rover that sits on the surface of Mars. The atmosphere of Mars is enriched considerably with the noble gas argon, in comparison to the atmosphere of the other planets within the Solar System. Unlike carbon dioxide, the argon content of the atmosphere does not condense, and hence the
Photorespiration times more abundant, and in solution is 25 times more abundant than . The ability of RuBisCO to specify between the two gases is known as its selectivity factor (or Srel), and it varies between species, with angiosperms more efficient than other plants, but with little variation among the vascular plants. A suggested explanation into RuBisCO's inability to discriminate completely between and is that it is an evolutionary relic: The early atmosphere in which primitive plants originated contained very little oxygen, the early evolution of RuBisCO was not influenced by its ability to discriminate between and . Photorespiration rates are