The primary difficulty is the fact that we do not know all of the organisms that currently exist in the world along with those that existed in the past.
Answer:
Their cells are eukaryotic is the right answers
Explanation:
I hope this will help you :)
Well first i just wanna say that life on mars has been discovered,not little green men but Bactria found on the surface and small traces of water have been found as well. some forms of life need little water to survive (like bacteria) but they still need water so yes there is water on mars the question is will we find it.